Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Inferno on March 18, 2018, 05:35:45 PM
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(sorry for double posting. I posted this in FAQ before realizing this was a general area)
Hello all.
Noob here.
I'm using the popular Chinese interface board and building up a system. I have the Toshiba drivers and all that. (If anyone needs the actual hardware items specified then it's no problem to get them for you)
It's taken a few weeks to iron things out to this point. First I had a faulty power supply. It was supposed to be a 12V supply but only putting out 2.6v. Now I'm using a 24v 20A power supply It's overkill but I already had it so that's where I'm at.
I'm using NEMA23 motors that are 8 wire but have isolated the 4 wire configuration.
My PC is Windows 7 32-bit fresh install.
Mach3 software is a fresh install, but a demo version (don't know if demo acts different than official version)
Parallel cable is new.
5v power to interface board is supplied via USB cable that I isolated the positive and ground (just occurred to me that I didn't test the voltage on the USB power wire)
Through trial and error I found out that I had the wiring set up as common cathode and changed everything to common anode (+)
Last night I was not getting any results, per usual, and then after adding the common anode the X axis worked. Y, Z, and A were still holding, no matter what test I ran.
This morning I thought I'd start swapping things around to rule out different things being problems. I disconnected the steppers and then tested them one at a time and verified that all the steppers were good.
I disconnected all the driver blocks and tested them one at a time. They all work with the X-axis test but none work with any other axis test.
I replaced ALL the wires from the interface board to the driver blocks.
I had a second interface board so I disconnected the old one and installed the new one and get the exact same results.
X-axis will work as configured but no other axis will.
I checked the address of the parallel port and it matches Mach3.
My motor outputs are
X - 3/2
Y - 5/3
Z - 7/6
A - 9/8
I have tried switching to 2/3, 4/5, etc and it won't work, even the X axis won't work at that point.
I can provide screen shots as needed.
Any help appreciated.
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This is what I have for Printer port settings
(http://www.fernohosting.com/CNC/lptpsettings.png)
Mach screen for parallel port
(http://www.fernohosting.com/CNC/MachSettings1.png)
Pinouts
(http://www.fernohosting.com/CNC/MachSettings2.png)
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Hi,
do you have a manual for the board? How about some pics.
If the board is all in one, quite common amongst entry level Chinese boards it may be that one or more of the drivers
is faulty and need repair or replacement.
Were you replacing faulty components consider buying separate drives and controller, then if one fails you don't have to
throw out the rest.
Craig
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Here's the manual for the board.
https://warp9td.com/images/BOB_Vendors/StepperOnline/ST-V2.pdf
The drivers are single.
I've switches all the components around to diagnose everything and all checks out OK. With different drivers and a different controller, I get the exact same results.
I'm with you on the cheap Chinese components so I bought double everything. I have 2 controllers and 8 drivers to work with as well as about 20 stepper motors.
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Here are actual pictures of what I currently have set up.
(http://www.fernohosting.com/CNC/20180318_170508.jpg)
(http://www.fernohosting.com/CNC/20180318_170523.jpg)
This picture is of the A axis driver setup. The other three are set up the same.
The wires are kind of a rats nest as I tried to narrow down anything I had hooked up wrong and the breakout board is set there temporarily
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Could the problem be that the computer uses a ECP Parallel port driver?
If so, how do I fix that?
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Hi,
I think it possible that you require two power supplies, one you've already hooked up but try hooking up the
other one, that is the USB cable back to the PC, it provides power also.
Craig
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Hi,
I think it possible that you require two power supplies, one you've already hooked up but try hooking up the
other one, that is the USB cable back to the PC, it provides power also.
Craig
The +5 and gnd in the upper left of the above photo is a 5v power from the USB on the puter. I still need to check to make sure it's outputting 5v.
The other USB on the board, from what I've read, is optional. You can either provide +5 from the computer where I have OR you can plug in a USB cable or both (but I read that on the internet so it HAS to be true, right ;)
I did it that way because, despite the fact that I know I have FIVE usb flat to usb flat, I can't find them.
I can pick up another USB cable tomorrow and give it a try, however.
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Hi,
Hi I think that 5V supply you have provided if for the output side of the opto isolators. The USB I would expect
to be on the input side. I would be tempted to try the USB cable trick.
Craig
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Thanks. Will give it a shot.
One of the tutorials I watched on youtube showed that there needed to be both because of a bad bridge on the board. He was showing where to run a jumper.
I will pick up a USB cable and give it a shot.
Thanks
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Hi,
some boards definitely require two supplies, one for the input side and a separate one for the output side.
Some require yet another for an isolated 0-10V analogue signal to your VFD.
Craig
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Looks like your board Needs pin14 as enable, have you configured this ?
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From your earlier picture you have the +24V and GND connected to the wrong side of the breakout board :-\
Tweakie.
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and you have common anode wiring, Setup for Motor Outputs should be dir low aktive and step low active enabled.
just by reading the Manual.
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Looks like your board Needs pin14 as enable, have you configured this ?
I'm not sure what you mean. I have an enable ire running from the board #14 to all the drivers. Is there something in Mach3 that needs to be configured that way?
From your earlier picture you have the +24V and GND connected to the wrong side of the breakout board :-\
Tweakie.
I'm not sure where you see that. I triple checked and the 24v supply is correct.
and you have common anode wiring, Setup for Motor Outputs should be dir low aktive and step low active enabled.
just by reading the Manual.
This is another spot where things get weird.
When I test the X motor with the boxes checked, the motor works but is choppy at lower speed.
When I test the motor with the boxes unchecked (red X) the motor runs smoothly.
Checking the boxes or not checking them has zero effect on the Y, Z, and A axis.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Today I got the proper USB connection to the breakout board. Nothing changed. The X still works and the others do not.
FWIW, Best Buy wanted $25 for a straight USB cable. If they wonder why people shop at Amazon, that's why.
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I think my next step might be to install Vista on the computer and then try Mach3 with the Vista install.
The seller of the breakout board specified XP in the description so I suppose I'd have to go all the way back to XP to rule out everything.
If it turns out that it works in Vista or XP but not in Win7 then I will have to reevaluate things.
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I'm not sure where you see that. I triple checked and the 24v supply is correct.
This picture shows quite clearly that the +24v and GND are incorrectly annotated.
Tweakie.
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Hi,
well spotted tweakie.
To OP,
I don't think going to Vista or XP is going to help. If DriverTest.exe shows positive results that's enough.
Craig
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I agree w Craig. You have some weird sort of wiring fault.
Cheers
Roger
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Quote from: TPS on March 19, 2018, 04:29:09 AM
Looks like your board Needs pin14 as enable, have you configured this ?
I'm not sure what you mean. I have an enable ire running from the board #14 to all the drivers. Is there something in Mach3 that needs to be configured that way?
see Picture enable
I'm not sure where you see that. I triple checked and the 24v supply is correct.
see picture 24V it is the opposite side
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I did wonder why you would feed +24 V into an optocoupler ... But I do not know the board.
Cheers
Roger
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Hi,
and unless theres some current limit you can be bound that the opto LED is fried.
Craig
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or poached.
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Thanks for the input guys.
I will check into the Enable line being checked wrong. In my head it makes sense that it could be the problem.
As for the wiring.
The picture is an optical illusion.
The first pin and second pin are common (visually bridged on the circuit board) and supposed to be +5. The third pin is gnd.
The second pin has the red wire and the third one has the black wire. Those are correct.
The 24v is within the rating of the board and connected to the proper spot.
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ok, i have rotated my pic, and put both underneath,
just to avoid optical Illusion.
and now i am out of ideas to Point you to the fault
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Hmm...
Second looks tonight will be had.
I apologize for not seeing this before.
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insight -> 100 points
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You were correct. I had the power supply on the wrong side. I feel so dumb.
Hooked it up correctly and the weird thing is nothing changed.
X still works. The other three axis do not work.
So, did I burn out two boards with them being hooked up backwards? And why would this stupid thing work with the X-axis no matter how it's hooked up? I know this is stepping outside of the Mach3 software questions at this point and do appreciate the help I've received.
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The attached photo shows a Homann Designs MB-02 BoB. The little red squares are my addition: each one is a Red LED, and they show the states of the input and output pins. This lets me see at a glance whether an input pin is actually working or not, and it lets me also see at a glance whether thoe output pins are working.
The LEDs acrosa the bottom of the pic are the motor pins, Step and Dir, for X, Y, Z, A. Consider trying the following:
g0 x0 y0 z0
f0.1 (Yes, this is a ridiculously slow speed, but bear with me.)
g1 x5 (assuming metric)
You should see one of the red LEDs blinking slightly. Those are the step pulses (albeit very narrow). One of the adjacent LEDs will be the Dir signal.
Now try
g1 x0
More blinking on the Step LED, but the Dir LED next to it should change state.
If you cannot see the Step signals, go to Ports&Pins and change the motor Step pins from Active HI to Active LO (or vice versa). This chould change the state of the LEDs while the system is not doing anything.
You do not have these LEDs on your Bob, but you could hook up some external LEDs to the screw terminals. Put a 220 ohm resistor in series with each LED. And you will have to figure out which way around the LEDs should go as well. They only conduct in one direction, but you can test for that between Gnd and +5V. A rather good idea would be to remove the +24V from the BoB completely while you do this.
All this will let you see whether the BoB output pins are doing anything.
Cheers
Roger
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You were correct. I had the power supply on the wrong side. I feel so dumb.
Hooked it up correctly and the weird thing is nothing changed.
X still works. The other three axis do not work.
So, did I burn out two boards with them being hooked up backwards? And why would this stupid thing work with the X-axis no matter how it's hooked up? I know this is stepping outside of the Mach3 software questions at this point and do appreciate the help I've received.
so have you tried to swap X an Y Step/Dir Connection on your breakout board ?
have you configured enable pin14 now ?
can you please post your XML ?
your axis dro's are changing on Screen if you move the other axis ?
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On screen DRO shows the axis are moving, all 4 of them.
I've swapped the x and y on the board to verify that the drivers are working and the motors are working. All 4 drivers and all 4 motors move when connected to the X axis on the breakout board.
I've enabled pin 14 and disabled pin 14 and neither had an affect. The X axis works both ways.
I will get the xml file tonight
Just to make sure the breakout boards aren't fried, I ordered two more. Hopefully they will get here by Saturday.
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Here's my XML file
www.fernohosting.com/CNC/Mach3Mill.xml
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All 4 drivers and all 4 motors move when connected to the X axis on the breakout board.
In that case we should assume that the drivers and motors are OK.
Which leaves the breakout board itself and the signals going into the BoB. You need to check both to see if there are any 'gaps' in the signal flow. Replacing the BoB is certainly one way of making these checks without any detailed probing.
I f replacing the BoB does not bring a cure, you will have to look further upstream.
Cheers
Roger
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All 4 drivers and all 4 motors move when connected to the X axis on the breakout board.
In that case we should assume that the drivers and motors are OK.
Which leaves the breakout board itself and the signals going into the BoB. You need to check both to see if there are any 'gaps' in the signal flow. Replacing the BoB is certainly one way of making these checks without any detailed probing.
I f replacing the BoB does not bring a cure, you will have to look further upstream.
Cheers
Roger
Yeah, kind of my way of thinking about it.
I'd do probing if
1) I knew what I was trying to see with the probe
2) It could be done with a multimeter
3) If I hadn't just blown off the probes on my multimeter. (more probes on the way)
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If I hadn't just blown off the probes on my multimeter.
The mind boggles! I have an image of a molten probe tips ...
You could EASILY make up a logic probe with a red LED and a 220 ohm resistor and a couple of bits of stiff copper wire. Ever so useful.
Cheers
Roger
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If I hadn't just blown off the probes on my multimeter.
The mind boggles! I have an image of a molten probe tips ...
You could EASILY make up a logic probe with a red LED and a 220 ohm resistor and a couple of bits of stiff copper wire. Ever so useful.
Cheers
Roger
Actually, there was no melting of probes. There was a bright white light a loud pop and the ensuing green blind spot in my vision.
Does it have to be a red LED? I have green, blue, yellow, amber, orange, IR, UV and white. ;)
I think I have some 220Ω resistors around here somewhere.
I know I have blank multimeter probes that I could morph into a holder for an LED and resistor. hmmm.
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It can be any colour you want.
I suggest that neither IR nor UV are good choices as you can't see them :)
White is attractive but white LEDs require about 3.6 V, which is not going to work too well when you are checking 3.3 V logic chips. They might work, sort of. Red LEDs require about 1.2 V from memory.
Logic probes are much faster than multimeters, plus you can leave a few LEDs in the output screw terminals for a while.
I have some test boxes which consist of a numbered row of Red LEDs with a multi-core cable ending in a selection of Ezy-Hooks. I colour-coded the Ezy-Hooks to the resistor colour code. Hook the clips up, jiggle Mach3, watch the pretty lights flash.
Cheers
Roger
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I threw a little sarcasm in there for humor. It might have missed it's mark.
I wasn't finding a 220Ω resistor too easy so I am going to use a 560Ω and a blue LED. Just for style. I might even pull out a few and hook them up but for now, here are my results.
Without Mach3 running and the 24v supply turned off, I only have the 5v USB power on the BoB.
Probing the output pins I get the following
P2 -
P3 +
P4 -
P5 -
P6 +
P7 +
P8 +
P9 +
This tells me something is wrong
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ok had a look to your XML.
it seems to be bad, it contains only Step per, ACC and Vel infomation for axis 0 (x).
i know that Information is shown for the other axis in Motor Tuning, dont ask me why.
so i would start with a new fresh Profile, Setup axis should not take very Long.
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A blue LED has a higher voltage drop, above 4V (like a white LED). It is probably the worst choice for this. If you don't have a red LED, try an orange one. Basically, the longer the wavelength, the lower the voltage. (And a red LED is more like 1.8V - my bad.)
Now, fire up Mach and see if you can get any changes to those results by toggling the Active Hi/Lo boxes in Mach.
Cheers
Roger
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FYI, I bought 2 of these boards because they were cheap.
I was able to get them to drive the steppers after awhile but I was never able to get the analog output for the spindle to work.
I threw them away and purchased a motion control board instead. While I spent a lot of money on a Hiconn (worth every penny) there are less expensive options out there.
Cheap winds up being expensive in the long run.
My .02.
Mike
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cheap or expensive does not matter for the Moment.
without a propper XML None of them has a Chance to work.
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Hi TPS
Agreed.
I just wanted to add in the fact that even after he gets his XML straightened out he may be looking at other problems down the road.
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The cheap BoB is to build the machine, When I'm done building the machine, a better, more reliable BoB will be added. In the meantime, if I did burn up two boards then I'm only out a few bucks.
I am not sure about how to build a new profile for a new XML file but will give it a little effort in learning how. I'm sure it's not technically difficult, just time.
I do have red LEDs. I had a blue one already out. I can switch to red. Not a big deal. (I bought over a thousand LEDs for a project that was later cancelled).
I appreciate all the assistance.
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just start mach3.exe by doubleclick,
then create new Profile with Standard Parameter.
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As TPS said, let Mach do the work. It has the facilities.
Cheers
Roger
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Just started a blank profile. This should be fun
/sarcasm
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New profile did not yield different results.
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can you post your new XML
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can you post your new XML
Absolutely.
Here it is
http://www.fernohosting.com/CNC/TheNew.xml
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Back to checking wires and pins with LEDs.
Cheers
Roger
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Back to checking wires and pins with LEDs.
Cheers
Roger
I'm still trying to determine what I will see with the LEDs that I don't already see.
I have a few small breadboards and will certainly wire one up to see.
I'm assuming I should be connecting them to the Dir and Step pins?
I figure I can hook up 16 LEDs (18 with the enable) and set them to indicate high or GND, right?
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Step and Dir pins - yes, certainly.
Hi or Lo - yes.
Imho, the 1st diagnostic is 'does the axis work'? The second is to look at the pins with such a LED tool.
Cheers
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this profile is completly empty.
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this profile is completly empty.
I'm guessing that means the profile doesn't actually save til you exit the program? Or am I supposed to do something I didn't do to not have a blank profile?
The two profiles I've used were the standard Mill one that comes with the download and the New one that appears to be empty. The only thing I did with the new profile was set the motor outputs as that's all I need to focus on until I have them working.
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I was asked to check pins with LEDs.
Here are the results.
To explain what's going on with the board, I can select to ground the LEDs on one rail or supply +5 to the LEDs on the other rail.
The 8 LEDs represent the 8 output pins. X-axis is on the right side. Step pin is first, then Dir pin.
I have verified that the diagnostic board I made is functioning properly.
There is more to read after the images.
First I added +5V to the LED array. This is the result.
(http://fernohosting.com/CNC/grounded.jpg)
The lit LEDs are showing ground on the breakout board.
There was nothing else spectacular here.
Next I grounded the LEDs on the other array.
(http://fernohosting.com/CNC/Xdir1.jpg)
The X-Dir pin is lit and when I toggle the direction, it goes out
(http://fernohosting.com/CNC/Xdir2.jpg)
And when I engage the X step I can clearly see the X step LED working
(http://fernohosting.com/CNC/HighSignal.jpg)
NOW the interesting part
Or maybe not so interesting, depending on how much you know about this stuff.
If I have power to the breakout board, and it's hooked up to the computer through the parallel cable, I get the outputs above.
If I disconnect the parallel cable, the board, essentially, goes dead as far as the output pins are concerned. There is neither +5 nor ground once the parallel cable is disconnected.
So, the LED test verified exactly what I saw in the motor test. Only the X axis is getting a signal. The step and Dir on the other 3 axis is not functioning, whether set high or low in the output pin settings.
So, is it a bad cable? Bad port driver? Bad breakout boards? Time will tell.
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Isn't it nice when you can SEE the signals.
When things get really baffling I forget all about the high-level diagnostics, like board swapping, and I go back to LEDs to actually see the signal.
OK, now what happens to the Y & Z axes under similar conditions?
I am a shade concerned about how the BoB goes dead when it is disconnected from the PP, but more info is needed.
First, are you supplying power to the BoB when it is disconnected? (This may be a silly Q, but it has to be asked.)
Next, what happens when you tie one of the BoB input pins to ground via a 100 ohm resistor? Does this affect the state of the output LED?
A perfectly horrible possibility which you have not mentioned is whether the PP output from the computer is damaged. You can test this with the LEDs and Mach3 as well. Note that you may need to supply +5 V to the LED board.
Cheers
Roger
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Isn't it nice when you can SEE the signals.
When things get really baffling I forget all about the high-level diagnostics, like board swapping, and I go back to LEDs to actually see the signal.
OK, now what happens to the Y & Z axes under similar conditions?
Y and Z and A axis don't do anything. They stay as lit in the photos. No matter what I do, they don't change.
I am a shade concerned about how the BoB goes dead when it is disconnected from the PP, but more info is needed.
First, are you supplying power to the BoB when it is disconnected? (This may be a silly Q, but it has to be asked.)
I supply power to the BoB through the USB output from the puter.
Next, what happens when you tie one of the BoB input pins to ground via a 100 ohm resistor? Does this affect the state of the output LED?
I don't have any 100Ω resistors to try. I used all my 220Ω resistors that I usually use for pull down on my Arduino stuff. I can get more on Tuesday if needed.
A perfectly horrible possibility which you have not mentioned is whether the PP output from the computer is damaged. You can test this with the LEDs and Mach3 as well. Note that you may need to supply +5 V to the LED board.
Cheers
I don't have a lot of ways to otest the parallel port but did order a PP breakout board. Unfortunately they won't be here for a while. Having said that, I should be receiving my new 5 axis BoBs soon (could be in the mailbox right now) so I will try replacing those first.
At this point I'm thinking it's either the BoB, the parallel port, the PP cable or the Win7 driver (I saw another thread that mentioned their PP troubles after a Win7 update).
I know my hardware is good. That's a plus.
Roger
[/quote]
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Hi Inferno
Now I am a bit confused. (That's not hard.)
Is the BoB hooked up to the PP on the computer or via a USB connection? And how do you plug a USB cable into a BoB anyhow?
You may not WANT to be an electronics engineer, but if you are running a hobby CNC you WILL become one sooner or later. But that can be fun anyhow.
I am running Win7, ESS, 2xHomann Designs MB02 BoBs, Gecko 320s, Mach3 .062, and the whole hums away. I was running this morning in fact.
Cheers
Roger
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Hi Roger,
I too use Homans BoBs and back when I was still using PP I powered the Homan BoB by USB. The USB
did not have any signal capability just a convenient way to plug your device (BoB) into the PC power.
Craig
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The BoB I have uses the USB for power ONLY. So the PP is for communication but the USB is power and there's another place to connect power from a PC that's not in the USB cable but, apparently, the power is the same circuit.
So, no power is coming from the PP. Not that I'm aware of. When I had the PP hooked up but no USB there was no power in the onboard LED.
As for being an electronics engineer... let's say I hold my ground. Pun intended.
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USB -powered MB-02 ... It is so long since I had to even look at mine at had forgotten!
I power my ESS from the BoBs through the DB25, and the BoBs from a separate PS.
Cheers
Roger
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this profile is completly empty.
I'm guessing that means the profile doesn't actually save til you exit the program? Or am I supposed to do something I didn't do to not have a blank profile?
The two profiles I've used were the standard Mill one that comes with the download and the New one that appears to be empty. The only thing I did with the new profile was set the motor outputs as that's all I need to focus on until I have them working.
thats was i your "new" Profile:
<?xml version="1.0"?>
-<profile>
-<Preferences>
<Syskey1>0</Syskey1>
<DefDir>C:\Mach3</DefDir>
<Profile>TheNew</Profile>
<NewPath>0</NewPath>
<BR>0.0</BR>
<BG>0.0</BG>
<BB>0.0</BB>
<FR>0.0</FR>
<FG>0.0</FG>
<FB>1.0</FB>
<RR>1.0</RR>
<RG>0.0</RG>
<RB>0.0</RB>
<AR>0.7</AR>
<AG>0.2</AG>
<AB>0.7</AB>
<ER>1.0</ER>
<EG>1.0</EG>
<EB>0.0</EB>
<MatRed>0.0</MatRed>
<MatGreen>0.1</MatGreen>
<MatBlue>0.1</MatBlue>
<Running>1</Running>
<FirstRun>1</FirstRun>
</Preferences>
</profile>
and as i said, there is nothing (what is witch mach related)
--->The only thing I did with the new profile was set the motor outputs as that's all I need to focus on until I have them working.
and set step' per vel and acc for every axis in motortunig
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Scrap the 'new' profile and go back to the distributed one.
Get the output pins working (changing state) when you change the Active Hi/Lo settings in Ports&Pins/Motor Outputs.
Then set up speed& accelerations & try jogging back and forth.
Cheers
Roger
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Scrap the 'new' profile and go back to the distributed one.
Get the output pins working (changing state) when you change the Active Hi/Lo settings in Ports&Pins/Motor Outputs.
Then set up speed& accelerations & try jogging back and forth.
Cheers
Roger
None of that worked. Set high, set low, toggle, etc.
Nothing changed that the x axis was the only one firing.
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Oh.
May I interpret that as meaning that you could not get any signals from the Parallel port connector itself, except from the X axis pins?
If so, then I make the following deductions:
Mach3 and the parallel port driver are correctly installed and able to drive the X axis.
The other parallel port pins are not working, although you could check this further by trying to move the X axis onto some other pins.
All of which means, to me at least, that the parallel port chip on the computer motherboard may be damaged. If so, this is not recoverable (unless you replace the MOSTEK chip on the motherboard).
If correct, then your next choice is to buy an external pulse engine. I strongly recommend against a USB version as they are very prone to noise interference. Buy an ethernet one.
Cheers
Roger
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Oh.
May I interpret that as meaning that you could not get any signals from the Parallel port connector itself, except from the X axis pins?
If so, then I make the following deductions:
Mach3 and the parallel port driver are correctly installed and able to drive the X axis.
The other parallel port pins are not working, although you could check this further by trying to move the X axis onto some other pins.
All of which means, to me at least, that the parallel port chip on the computer motherboard may be damaged. If so, this is not recoverable (unless you replace the MOSTEK chip on the motherboard).
If correct, then your next choice is to buy an external pulse engine. I strongly recommend against a USB version as they are very prone to noise interference. Buy an ethernet one.
Cheers
Roger
I don't have the tools necessary to check the parallel port pins. I suppose I could monkey rig something but I'm too lazy today.
What pin in the parallel port provides a +5 signal and which one provides ground?
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OK, here's what I did, knowing I'm not sure of what I'm doing.
I disconnected my printer port.
I took a blue LED (I can switch a red one in if needed) and added in a 680 ohm resistor in series.
Using this image as a reference
(https://upload.wikimedia.org/wikipedia/commons/thumb/e/e0/Parallel_port_pinouts.svg/350px-Parallel_port_pinouts.svg.png)
I connected the cathode to pin 25 on my printer port.
Then connected the resistored anode to pin 2.
Using Mach3, I tried to cycle the X-axis. The LED didn't change.
I reset the X-axis pin2 to low and nothing changed on the LED.
Bottom line is that I don't know how to check the data output on the pins on the Parallel port with success.
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Hi,
blue LEDs have a forward voltage drop of about 3.3V and so with a what may be a 3.3V port the LED
would not light reliably. A red LED has a forward drop of around 1.2V and is suitable.
Craig
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Hi,
blue LEDs have a forward voltage drop of about 3.3V and so with a what may be a 3.3V port the LED
would not light reliably. A red LED has a forward drop of around 1.2V and is suitable.
Craig
Red LED made no difference in the diagnostics.
-
So, here's where I am.
I took a look at this video
https://youtu.be/uglCm_qsojk
Then I did what the video said.
I hooked the ground to pin 25 and then the positive on the multimeter to pin 2. It was reading 3.3V
I checked pin3 and it read zero. Then I pushed the up and down arrow and the output changed to 3.3V
I checked pin 4 and it was zero. I used the page up and page down and the pin read 3.3v.
The interesting part was that, once the pin went high (3.3v) it wouldn't go low again.
Still trying to figure out why X will work, though.
I only tested pins 2,3,4 this way. If they don't go low then there appears to be a problem in the computer.
-
It appears those pins are setup as direction pins.
If you move those axis in the other direction the
pins will change state.
olf20 / Bob
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It appears those pins are setup as direction pins.
If you move those axis in the other direction the
pins will change state.
olf20 / Bob
I was just doing what the video was saying to do. It was only to check to see if I was getting proper responses from the output pins on the parallel port.
I discovered that I can get all of the 8 "data" pins to function properly. I also discovered the left and right arrows on the X axis don't control both directions. Left controls the minus movement but "X" key on the keyboard controls the plus movement.
Likewise for Y and Z
Down arrow controls minus on Y and the "Y" key controls the plus.
Page down controls the minus on Z and "Z" controls the plus.
So, the parallel port is verified as functioning properly. Tonight I check the parallel cable the same way. If the parallel cable is working normally then I have verified that the BoB is the culprit.
-
Hi,
sounds like the parallel port of your PC has 3.3V output levels.
Is the BoB you are using 3.3V capable? If it is expecting 5V inputs it might describe your situation.
Craig
-
Hi,
sounds like the parallel port of your PC has 3.3V output levels.
Is the BoB you are using 3.3V capable? If it is expecting 5V inputs it might describe your situation.
Craig
That's a good point.
I should look into that further.
Thanks for pointing it out.
-
Here is one absolute that I got from my diagnostics.
Pin 2 on the parallel port emits on pin 3 on the cable.
It's a brand new cable and it's bad.
I suppose I could use a multimeter and map out the cable to find out if all the pins are off one or if they are all connected or whatever and then remap the program based on the outputs.
Or I could buy a new cable.
-
Pin 2 on the parallel port emits on pin 3 on the cable.
HANG ON!
Where are you getting your pin numbers from?
The pin numbers seen on a ribbon cable connector are NOT the same as the numbers we use for I/O pins on the PP. In particular, pin 2 in CNC numbering scheme is pin 3 on a ribbon cable.
Cheers
Roger
-
Pin 2 on the parallel port emits on pin 3 on the cable.
HANG ON!
Where are you getting your pin numbers from?
The pin numbers seen on a ribbon cable connector are NOT the same as the numbers we use for I/O pins on the PP. In particular, pin 2 in CNC numbering scheme is pin 3 on a ribbon cable.
Cheers
Roger
It was a simple continuity test.
Here's where I stopped
(http://www.fernohosting.com/CNC/badcable.png)
-
Ahhhh ...
I am not entirely sure I understand your diagram. If it really means that you got continuity between p21 at the left side and pin4 at the right side, then I am boggled. That is NOT a DB25 extender cable!!!!!!! I dunno what it is!
-
Ahhhh ...
I am not entirely sure I understand your diagram. If it really means that you got continuity between p21 at the left side and pin4 at the right side, then I am boggled. That is NOT a DB25 extender cable!!!!!!! I dunno what it is!
That is exactly what it means. I got continuity between pin 4 and 21.
I can't reassign that.
If I couldn't get another cable tomorrow, I'd split the cable and manually rewire it all for a test. For now I'll wait.
-
Weird. I don't see an edit icon. I would have edited the above post.
I felt that I should check the cable more and discovered that pin7 didn't connect to anything.
The cable is in the garbage now.
-
I take it the cable was 'collected' from a different bit of equipment.
You can't undo the shells and unsolder all the wires at one end?
Or do the connectors have injection-moulded covers?
Cheers
Roger
-
I take it the cable was 'collected' from a different bit of equipment.
You can't undo the shells and unsolder all the wires at one end?
Or do the connectors have injection-moulded covers?
Cheers
Roger
The cable was brand new, in a factory package. Molded ends.
It must have been a special cable. Didn't have anything special on the packaging though.
I'm taking my multimeter to the store with me tomorrow. It's an unusual store....
surplusgizmos.com
-
Take cable back to store for refund?
Cheers
Roger
-
Take cable back to store for refund?
Cheers
Roger
They gave me another cable. They tested it first.
There's an actual machine for testing DB25 cables. Who knew?
Now I have different results.
The second I plug the cable in, the relay triggers. That's cool. It could be a brake release or whatever or I could set it low in software or whatever. No biggie.
First I set the pinouts.
2/3 X
4/5 Y
6/7 Z
8/9 A
Tested X and it works for about 5 cycles or less.
Tested Y and it works perfectly
Tested Z and have zero movement
Tested A and no matter which direction it's supposed to move, it moves clockwise.
I checked wires a few times. I swapped the headers on the drivers (basically traded cables) and everything repeated the same indicating the problem is either in the wiring, or the BoB.
I ran three different XML files to come to this conclusion.
I got my new BoBs in today so tomorrow is swapping one in
-
The second I plug the cable in, the relay triggers. That's cool. It could be a brake release or whatever
That is possibly a function of the active Hi/LO levels around the place, inc on the BoB.
I made all my outputs Active HI so that the effect of a disconnected cable etc was just the same power-down.
This does not cover the motor output signals.
You should also check any use of the Enable outputs from Mach3. Under normal conditions you can happily avoid using any of them.
Tested X and it works for about 5 cycles or less.
????????
Use the LEDS and see exactly what is happening here.
Tested Y and it works perfectly
Good. You can/should also use this axis to check the drivers and motors for the other axes.
Tested Z and have zero movement
If the Z axis driver and motor check out OK when driven by the functioning Y axis, then the problem may be in the BoB or the Mach config. Guess what? LED time!
Tested A and no matter which direction it's supposed to move, it moves clockwise.
OK, Step pulses getting through but not the DIR signal. LED time and check Mach config.
No worries. You are on your way to having a good understanding of the Mach3 signalling, which will ALWAYS be an advantage. You also now have a functioning LED diagnostic tool.
PROGRESS!
Cheers
Roger
-
Thanks for chiming in.
I sort of took your advice. I built new probes on my multimeter and used it instead of the LEDs. It was faster.
I checked continuity across all my grounds, voltages and connections.
I saw inconsistencies so I figured, since I still had time tonight, to swap out the boards.
I was meticulous about the wires. I found, when I took them off the other board, that a strand of wire had bridged one of the connections. That's fixed and ferrules have been ordered to prevent it again.
Powered up the new board (different manufacturer but same design and components) and ended up with a repeated set of tests. Z still didn't work but X now worked 100% of the time but, like A, it only spun in one direction.
Back to the cable I went and discovered that this cable was also not giving good signals from mach3 to the end of the cable.
New cable woes....
I didn't have it in all the way.
It was a very tight fit to get it in and it almost snapped into place but I now have FOUR working axis.
Thanks for hanging in there with me.
I DO have a little better understanding of Mach3 and can now proceed with tuning the motors (just to learn) and building the next stage of the project.
-
Go for it.
Cheers
Roger
-
You are doing great!
When I converted my knee mill, I went thru the same type of things.
This forum helped got my machine up and running, and
most importantly making chips.
It is very rewarding!
olf20 / Bob
-
Thanks for the encouragement.
Last night I played with the tuning a little. It seems to not run the steppers as smoothly as I thought, at low speeds.
At faster speeds the motors will stall and lock.
I'm going to be playing with the tuning a lot, I think.
I'm wondering what the purpose is for having such a wide possible range on the tuning sliders. It defaults at 2000 steps per revolution (which my motors don't like) and then has a long range of speeds and possible acceleration.
I assume part of it is that I should have my stepper drivers and the steps per revolution matching before I try to tune it too much. Right now I think I have the driver set to 400 steps.
It's all part of the learning process, I'm sure.
-
There is a steps per unit calculator here; http://www.machsupport.com/forum/index.php?action=dlattach;topic=16315.0;attach=23771
Tweakie.
-
Stepper motors?
What is the maximum voltage allowed on the DRIVER (not the motor),
what is the power supply voltage you have,
and what is the current setting on the driver,
what current is the motor rated for?
Cheers
Roger
-
Stepper motors?
What is the maximum voltage allowed on the DRIVER (not the motor),
what is the power supply voltage you have,
and what is the current setting on the driver,
what current is the motor rated for?
Cheers
Roger
From memory.
The drivers are rated to 48v, my power supply is 24v
Current setting on the driver is 1amp.
Stepper motors are rated 1.2 Amp and 4.7v
I will correct this info if it is erroneous
-
OK. 24 V is not enough. You should try to get a LINEAR supply rated at 40 - 42 VDC. I recommend you do NOT use a switch-mode PS as these give the drivers a very hard time and may cause the sort of malfunctions you are currently seeing.
Linear PS: a transformer, a diode bridge, and one or two big capacitors. Many drivers do in fact specify that you should use this sort of PS and NOT a switched one.
If you are not familiar with the maths for PSs, then a transformer rated at 30 VAC and ~6 A would be wonderful. A 100 VAC diode bridge also rated at 6+ A is fine. Caps - one or two 10,000 uF caps rated at 63 VDC would be fine. Putting a fuse in the primary (input) might be smart.
Cheers
Roger
-
I don't know why 24V power supply isn't OK. Here's my logic.
First, I misspoke. The steppers are 5.1v/ph, 1A/ph
The actual number is 23LM-C304
And the reason I think the 24v power supply will work fine is because these motors were originally mated to this power supply. In fact, this power supply fed 6 of the steppers, not just four. It's not some cheap Chinese power supply. It was in service for over 10 years with no issues.
The rest of what you said is something I will keep in mind. I don't know half of what you were saying but I get the jist and could figure out the other half if needed. I'd prefer, if necessary, to buy an actual power supply that doesn't need any tinkering.
Not sure what a LINEAR vs switch-mode power supply is.
Still learning though.
-
Hi,
yes your steppers will work with 24V but they will be able to go a lot faster without losing steps with a higher voltage.
A linear supply uses a transformer to reduce 230V to 30V. Transformers of this power level are quite big, heavy and quality wound ones are expensive.
Switchmode supplies use electronics to generate AC at many kHz and can use a much smaller and cheaper transformer. At high power levels they are
cheaper than linear supplies but they are not as reliable or forgiving. By all means use you switch mode supply but if you see smoke coming from it and/or
your stepper drivers you will know that it was a poor choice.
Craig
-
There are some good tutorials on the Gecko.com web site. You may find them helpful in understanding what we are saying.
Cheers
Roger
-
Cool. Thanks for the advice.
I'm still trying to understand the ministepping feature.
For what it's worth, I lose steps at low speeds.
-
For what it's worth, I lose steps at low speeds.
Weird!
That could be interference between the switch-mode PS and the drivers.
Cheers
Roger
-
I think a lot of the problem might be that I hooked up my 8 wire steppers wrong.
I, mistakenly, thought I just needed 2 of the 4 coils wired and isolated the other 4 wires. It turns out I need to hook them all up either unipolar or bipolar connections.
The trick will be to find out which wires go to which coil.
These are 23LM-C304 motors. I still haven't found a color coded wiring diagram for them.
I'm not ignoring the advice of the PS issues. I just think I should have better results (even if not perfect) than I am.
-
I'm not ignoring the advice of the PS issues. I just think I should have better results (even if not perfect) than I am.
That sort of attitude will get you support from just about everyone here. Go for it!
Cheers
Roger
-
This may or may not provide a starting point:
http://www.theprojectasylum.com/electronicsprojects/componentdata/minebea-stepper-motor-winding-wiring-diagrams-circa1999.html
Cheers
Roger
-
I think a lot of the problem might be that I hooked up my 8 wire steppers wrong.
I, mistakenly, thought I just needed 2 of the 4 coils wired and isolated the other 4 wires. It turns out I need to hook them all up either unipolar or bipolar connections.
The trick will be to find out which wires go to which coil.
These are 23LM-C304 motors. I still haven't found a color coded wiring diagram for them.
I'm not ignoring the advice of the PS issues. I just think I should have better results (even if not perfect) than I am.
Hi, been following this thread from afar...
That is a major blooper right there - with only two coils running you will certainly get poor results at low speed due to the lower momentum of the rotor - once running at speed it will overcome the missing steps, of course you will only get half or less power from them ;)
I am unsure of the PSU options here - I have three machines all running on switch mode PSU's ranging from a plasma table to a large mill with servos, all run ok. One of the leading UK suppliers recommends SM PSU's for their drives/motors as well.
However, that being said, I do have the parts for a linear PSU on hand for my plasma table as they are pretty tough on electronics and also could do with a little more voltage that SM PSU's do not offer. When you have larger motors and high acceleration settings I do think a linear PSU is good as they can give much higher surge currents faster than SM ones but with small motors/machines then easy is the way forwards I think.
Wiring your motors correctly/fully will likely fix your issues ;)
-
Hi,
having your steppers wired correctly is mandatory to get them to work properly. As you point out you need to get the best from them no matter what power supply you
use.
If you can find documentation...all well and good. If you can't then the trouble starts. There are two basic approaches you could take:
1) Using instrumentation including an oscilloscope, sinusoidal signal generator and resistance meter make measurements to work out the wiring
2) Write down all the possible combinations of wiring and using what instruments you have eliminate as many as you can and thereafter try each remaining combination to find the best
performing combination.
Do you have electronic test gear or know someone who has and will help?
I bought a new old stock 5 phase Vexta stepper. It has 10 wires, 2 for each phase. They are electrically isolated from each other so determining the pairs of wires was easy.
There was documents that came with it and my measurements were confirmed. What the documents did not cover was the phase of each winding. I was able to determine
the phase by feeding one winding with a 1kHz sinusoid and then measuring the phase of the induced voltage in each of the other windings.
To do the same thing with a two phase stepper would be similar. Determine the 4 pairs of wires with a multimeter. Feed one winding with a sinusoid and measure the induced voltage
on each of the remaining windings. There will be one which is in tight phase (antiphase) of your input being the winding in the same slots or phase of the stepper. The remaining two windings
will be slightly less strongly coupled and will be the two windings associated with the the second phase of your two phase motor.
This process can be confusing and you will need a solid understanding of transformer action to decode the measurements you make. 'Character building'....mind you I don't have any character
and don't really want to start now!
Craig
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I don't have access to an oscilloscope but have basic knowledge of how steppers work and a logical mind so this is what I am doing.
To isolate the paired wires (coils) I am bridging wires, two at a time, and spinning the motor by hand. When i feel the pulsed resistance, i know I have a coil.
Using this method I will end up with the four pairs.
Since the wires are color coded, I can, probably, deduce left and right pairs by picking the solids, and calling them right, and the stripes and calling them left.
So, I have four pairs, two left and two right.
When I bridge the two solid pairs, I have a smooth resistance. When I bridge the two striped pairs, I have smooth resistance.
So, to match the left and right I am using the same method.
First I bridge two solid wires. I have stepped resistance. If I add in pair of striped wires, bridged, I will either still have a stepped resistance or I will have a smooth resistance. If the pairs match then it's stepped resistance.
Using this method I have the paired coils.
I hooked these up in bipolar series last night and had a very smooth motor but the direction wasn't reliable. This tells me one set of coils was backwards. Just one though.
I now have a diagram written out that will help me tonight. It was too late last night to keep working on it or I would have had it ironed out then.
Stay tuned.
-
I think a lot of the problem might be that I hooked up my 8 wire steppers wrong.
I, mistakenly, thought I just needed 2 of the 4 coils wired and isolated the other 4 wires. It turns out I need to hook them all up either unipolar or bipolar connections.
The trick will be to find out which wires go to which coil.
These are 23LM-C304 motors. I still haven't found a color coded wiring diagram for them.
I'm not ignoring the advice of the PS issues. I just think I should have better results (even if not perfect) than I am.
Is that number correct?
Here is data for 23LM-C304 motors and it only shows 4 wire/2coil ???
http://web.archive.org/web/20050224182758/http://www.taxibooking.net/23LM-C304-51V.pdf
-
I think a lot of the problem might be that I hooked up my 8 wire steppers wrong.
I, mistakenly, thought I just needed 2 of the 4 coils wired and isolated the other 4 wires. It turns out I need to hook them all up either unipolar or bipolar connections.
The trick will be to find out which wires go to which coil.
These are 23LM-C304 motors. I still haven't found a color coded wiring diagram for them.
I'm not ignoring the advice of the PS issues. I just think I should have better results (even if not perfect) than I am.
Is that number correct?
Here is data for 23LM-C304 motors and it only shows 4 wire/2coil ???
http://web.archive.org/web/20050224182758/http://www.taxibooking.net/23LM-C304-51V.pdf
Yes, that number is correct. This seems to be an oddball one but I have over 25 of them.
-
I just found this sheet that appears to match my motors.
I need to translate it from German (I think) but the color combination looks the same.
http://www.robotikhardware.de/download/23lmc30415.pdf
-
Wire it up and see how it goes!
You can series the winding in each phase or parallel them.
Cheers
Roger
-
I need to find a different way to figure out the coils.
I suppose there are only a few different configurations that are possible.
I've tried in parallel. I've tried in series. Some were more fruitful than others. Some danced on my glass coffee table. Quite loudly, I might add.
I'm still not getting a smooth acceleration.
Yes, It might be the power supply. I understand that. It's just bugging me that it "shouldn't" be the power supply as this power supply went with these motors and worked great.
-
Hi,
the highest power/torque will be achieved with a parallel combination. It will also be the combination which gets hottest fastest.
The trick to wiring them in parallel is to ensure that the two windings of the pair are co-phase. You either have to measure it by feeding a signal into one
coil and monitor the phase of the voltage induced in the second.
The diagram you posted suggests that you have enough information to do it by trial and error if the groupings of the four windings into two phases can be believed.
Wire the two phases in what you think is co-phase and try it. The swap the one winding in one phase only and try it, if its better then that phase has now got co-phase windings,
if not they were co-phase in the previous wiring condition. Now do the same excerise with the other motor phase.
Once you've got it correct don't keep fiddling with it. It will just keep introducing more diagnostic variables when you are actually trying to eliminate them.
Craig
-
Hi,
the highest power/torque will be achieved with a parallel combination. It will also be the combination which gets hottest fastest.
The trick to wiring them in parallel is to ensure that the two windings of the pair are co-phase. You either have to measure it by feeding a signal into one
coil and monitor the phase of the voltage induced in the second.
The diagram you posted suggests that you have enough information to do it by trial and error if the groupings of the four windings into two phases can be believed.
Wire the two phases in what you think is co-phase and try it. The swap the one winding in one phase only and try it, if its better then that phase has now got co-phase windings,
if not they were co-phase in the previous wiring condition. Now do the same excerise with the other motor phase.
Once you've got it correct don't keep fiddling with it. It will just keep introducing more diagnostic variables when you are actually trying to eliminate them.
Craig
Once I get it right, I'm done fiddling. LOL
I know which coils pair. I'm not worried about that. I verified it earlier as well.
To find the polarity of the paired coils, I excited one of the coils to see the step. I kept trying different combinations of polarities and coils until it did NOT step from the known step.
Once I had that pair set with the proper polarity I was able to do the same with the other set of coils.
When I was done I compared to the diagram I posted and they match. Basically, I double checked them.
Now I have them wired in parallel and just need to find a way to make them step clean.
-
Does your driver include 'anti-resonance'? Without this, you can sometimes get quite poor performance.
Cheers
Roger
-
Does your driver include 'anti-resonance'? Without this, you can sometimes get quite poor performance.
Cheers
Roger
Don't know, I will have to look into that.
I'm using a VERY popular driver. I can't imagine it being that popular if it's built like crud.
-
When drive A is half the price of drive B, you may find that Drive A is VERY popular.
But when Drive A is half the price of drive B, I ask myself WHY is it so much cheaper?
Generalities ...
Cheers
Roger
-
When drive A is half the price of drive B, you may find that Drive A is VERY popular.
But when Drive A is half the price of drive B, I ask myself WHY is it so much cheaper?
Generalities ...
Cheers
Roger
True. And there were cheaper drivers.
I'm not giving up on the drivers til I test them with a 4 wire stepper.
-
If you can figure out which are the A coil and which are the B coils, you can simply use one A coil and one B coil. The end results may be very similar.
Cheers
Roger
-
That's how I started.
The weird thing is that every (good) configuration yields similar results. Low speeds are choppy and there are missed steps when running a g-code.
-
This morning I changed the stepper driver configuration to 400 steps per revolution and it seems smoother. I ran my test g-code and the stepper returned to zero after the test. This is the first time it's done that.
I do still get extra "vibration" at a lower speed but it appears to hold steps so that's a plus.
There are other configurations I can pursue on the driver so I'll probably play around a little more.
I still need to get some new steppers with more strength when I do the actual build so I don't know that I need to worry about these 8 wire motors too much. I figure if I can make them work perfect then a four wire motor would probably be childs play.
-
First posting on steppers: 18/March
This posting on steppers: 31/March
The learning curve has been steep but effective?
Cheers
Roger
-
The extra vibration at certain speeds sounds like resonance.
Mass i.e. a load should alter that but sometimes you have to work round it.
Steps per rev is usually fixed and written on the motor - generally 200 or 1.8deg per step, do you mean you set micro steps to 400??
-
First posting on steppers: 18/March
This posting on steppers: 31/March
The learning curve has been steep but effective?
Cheers
Roger
I'm not sure if this was sarcasm or praise.
Most of the time has been spent trying to get the stupid bad cable diagnosed. Now that that is over with I am free to tune.
The extra vibration at certain speeds sounds like resonance.
Mass i.e. a load should alter that but sometimes you have to work round it.
Steps per rev is usually fixed and written on the motor - generally 200 or 1.8deg per step, do you mean you set micro steps to 400??
I think you might be right about the resonance. I have everything mounted to 1/4" plastic sheets right now so any vibration is enhanced in sound. Watching the zip tie I have on the motor shaft helps me see if there's more vibration or less depending on the configuration.
Yes, the motors have the steps per rev on them and yes it's 1.8 deg per step. The drivers, however, have the capability to microstep (apparently) and when I set the drivers to microstep I seem to have a better result in the accuracy of maintaining step. If I set the driver to 200 steps then I seem to lose staps. If I set it to 800 steps then I seem to have a better accuracy.
If I end up using the most accurate settings then I'm going to have to have some serious gear reduction in the final build.
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I'm not sure if this was sarcasm or praise.
It most emphatically was not sarcasm or criticism.
Actually, I think once again it illustrates the differing senses of humour between Australians and Americans. I get into so much trouble over it.
If I end up using the most accurate settings then I'm going to have to have some serious gear reduction in the final build.
Not so. Mach3 looks after the micro-stepping. Using it does not mean any changes in gearing. What micro-stepping can do is to make motion smoother. So, do all your calculations about gearing withOUT considering any micro-stepping.
Cheers
Roger
-
I shall than you, then, for what could be considered a compliment. ;)
I have a dry sense of humor, myself, so no worries.
What I had read, and gathered, is that microstepping would have less torque than full stepping, hence the thoughts on adding gear reduction.
The trade-off being that gear reduction would add in a component of inaccuracy or slop when shifting directions. This is something I do not want to introduce, especially when I migrate from the CNC build to adding CNC capabilities to my home mill and lathe. I had considered other methods to insure the accuracy of the direction change in that project, though. I imagine that, once it's calculated, I could add the necessary correction to the G-code generation and/or the Mach3 profile. But that's a way down the line so I won't focus on it yet.
My next step is to determine which setting on my drivers will yield the best results. And determine which stepper motors I want to invest in.
I wanted to go to a NEMA 34 with dual shaft (dual shaft for my X-axis only needed) but there's a decent set of NEMA 23 with a reported over 400 oz/in rating
It's a few dollars more I can get 1600 oz/in in a NEMA 34.
When I say "a few dollars more" I mean it's almost twice the price.
My CNC mill will only be a 24" X 48" (or 650cm X 1300cm for the Aussie)
-
Hi Inferno
Micro-stepping does not really have significantly less torque. There are many myths on the web, and this is mostly one of them. The explanation of the origin of the myth gets rather technical: lets just skip it for now and ignore it. Do all your planning on the assumption that you do not have micro-stepping, even to the point of getting Mach going without it. Then ... if you decide you want to implement 8x micro-stepping, do so, and change the calibration in Mach by the same factor. You will get slightly smoother movement.
If you wish to have some 'gearing', do NOT use metal gears, or gears of any sort. Go for modern toothed belts, such as GT2. They work extremely well, do not have backlash, and have oodles of power rating. But note: 'modern' toothed belts. The older and possibly better known 'timing belts' do have backlash and should be avoided. They will only bring grief. Fwiiw, I use a GT2 9 mm wide toothed belt to give a 3:1 reduction on each of my axes. I replaced the older timing belts the machine came with. The spindle still has a timing belt drive ... so who cares?
The resonance problem is more technical - but it is also far more important. If your drivers do not support resonance suppression, then there are going to be some limits to what you can do. You will have to avoid a middle speed band. That too is possible at the start. You will find out about that when you get going.
Stepper motor size: my CNC machine is not large - it is a dual axis CNC 4-axis MACHINE, not a router. It has 300 W DC servo motors on the axes, 3:1 reduction, 5 mm pitch ball screws. I have current meters on each driver. I very rarely see any movement in the meters at all. I do not think they ever draw more than 10 - 20 W at full slewing speed. I rather suspect that a lot of builds have motors way bigger than they will ever need.
Of course, once you have built a CNC, you can always make new improved parts for it! Some of our readers seem to spend most of their time doing just that. :)
Cheers
Roger
Cheers
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Hi,
the real figure of merit when it comes to steppers is inductance. Inductance affects how quickly current can build up in a coil. Lower inductance windings mean that the current builds up faster
and therefore the stepper can rotate faster without a significant reduction in torque.
Not all manufacturers make plain what the inductance is on their motor, I would ask. If they can't tell you don't touch it. For 23 size steppers 2mH or less is good. For 34 size look for motors of 4mH or less.
Craig
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And putting two windings in parallel effectively halves the inductance too.
Cheers
Roger
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Right now I have the windings in series. So should I put them in parallel for a better performance?
(still trying to figure out why they even have an 8 wire model.
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Hi,
the parallel combination is better for performance. Provided it does not get too hot that's the way to go.
A four winding two phase stepper can be run flexilbly as unipolar or bipolar and therefore potential OEMs sales increase because of the flexibility of application.
Craig
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Hi,
the parallel combination is better for performance. Provided it does not get too hot that's the way to go.
A four winding two phase stepper can be run flexilbly as unipolar or bipolar and therefore potential OEMs sales increase because of the flexibility of application.
Craig
When I had them in parallel they did get pretty warm. Maybe 110-120 degrees F
I've read unipolar and bipolar several times but still can't fully comprehend what that means.
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Yes, you will get better performance by putting them in parallel.
Yes, the stepper motor will get warm. More advanced drivers not only have anti-resonance circuitry, they also have the ability to reduced the holding current (and hence the heat) when the motor is not turning.
Unipolar vs bipolar: that is more a matter for the driver than the motor. All stepper motors have to be 'bipolar': the field has to reverse in each winding. Stepper motor primers are on the web.
Cheers
Roger
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I would NOT go with Nema 34's - they are big, slow and need a serious setup of power supply and drives (high voltage/high power) to make them dance. If i were calculating I needed a Nema34 I would switch to AC servo's without further thought, a small AC servo can out perform a Nema34 easily.
IIRC the average "good" setting for micro steps is 1000 but it can be anywhere you want really, just remember that the higher you go, the faster Mach3 has to generate pulses - theres a limit (if you are using M3 to generate pulses that is)
Definitely belts as mentioned, another good profile is HTD5, very common and no backlash, its the shape of the teeth that matter, anti backlash belts generally have round profile teeth whereas the old ones had trapezoidal shapes.
Getting the balance between motor power and machine build is pretty much impossible first time - the calculations are horrendous so most builders think they need oodles of power and look to Nema34's etc - this then opens up a world of pain because you now have speed issues and your machine, although it can easily break a 25mm tool off, cannot move very fast when needed ;)
On most machine builds, It seems the most common solution now is for Nema23/4Nm on something like a 70v power supply with good anti-resonance digital drives. I have these on my plasma table, and even though I'm only running 48v it can certainly shift when needed, One on X and two on Y, Z has a smaller 3Nm motor. This is gear on rack drive so not good for milling etc but adequate for plasma which has zero axis load.
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I THOUGHT I HAD IT!!!
I had made a lot of different configuration changes. Finally I found one where the X-axis (working with only one axis til I found something that worked) was working flawlessly.
I had it set to single step mode and ran a test G-code file and after three times running the file I checked and the X-axis hadn't lost a single step.
Also, during this configuration searching I realized I wasn't dropping as many steps as I had thought. My rotational indicator (a zip tie on the shaft of the motor) was slipping as it went around the table side of the arc.
Anyhow, after the test, verifying that the X-axis hadn't missed a step, I hooked up the other 3 motors with the same configuration. Then I ran the test file again.
The test file is just a spiral design. Nothing fancy.
After a single run of the test file I found that all three active axis had dropped a LOT of steps. As many as 60, based on the angle of the indicators.
So, I am thinking that it's very likely that the problem is that the computer can't communicate properly with that many steps at the same time. Possibly the 3.3v on the parallel port issue.
Without an oscilloscope I won't be able to "properly" diagnose this. It's going to be some trial and error.
The other possibility is that the power supply can't handle 3 motors but my better judgment tells me this power supply ran (checked again) SEVEN of these motors in their original machine so it should be able to handle three of them.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
On the other side of things, I do believe I will stick with a NEMA 23 setup. There are a lot more options available in the 23 and even the dual shaft that I'd like to have for the X-axis. Plus they are a lot less expensive than the 34's.
If I need more torque I can always gear them up/down a little.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
I'm not ignoring the advice on the timing belts. It made it into the noggin. I've been toying with belt timing, lead screws, gear drive or ballscrews. My mill will definitely have ballscrews (bought two axis of them already) but the CNC router will probably be run on timing belts or gear rails.
Now I'm going to see about increasing the parallel output to 5v if there's any possibility. I can't help but wonder if a PCI card would deliver 5v.
I'm also going to try running the file again with the network controller unplugged (it's a USB type).
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Sounds like there is still some work to do there ;)
Even with ball-screws, belt connection is common and helps a lot with resonance issues etc, it also allows you to easily adjust ratio up/down without major alteration.
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Went into the BIOS on the computer. It was selected as a PS/2 port. I changed it to EPP and measured the voltage. Still about 3.3
Tried to run code. No change in the performance. Still drops steps.
I checked the voltage at the drivers, coming from the BoB and it measured 4.25v so the BoB is allowing the USB power from the puter to switch based on the signal from the PP. Basically there's USB power coming through to the drivers.
I'm considering hard wiring directly from the computer power supply to the BoB. It would allow more amperage to be supplied to the BoB than the USB can supply.
Good point on the timing belt on the ballscrew. I had considered that the single step on the stepper on a 5:1 ballscrew allows for a .001 precision which would be plenty for my needs. Having a gear reduction and microstepping on the motor could make that smaller (not needed) but also a lot quieter.
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Hi Inferno
Oh, things are not that bad. There is usually more than one bug, and you have dealt with the first one.
Zip tie - hilarious! Gowachin Law: first exonerate the judge. Ah well.
likely that the problem is that the computer can't communicate properly with that many steps at the same time.
No, I do not think that will be the solution, not at all. That is not how Mach works. I think you should assume that the right pulses are coming out the PP. From memory, EPP is the right setting. Also remember that when you exercise the X axis only, it works perfectly.
These are all steppers? If so we can discount encoder noise.
I see two main possibilities: pulses are being lost going through the Bob, or the drivers are missing some pulses. But the loss is most likely due to the extra load when you go multi-axis. Something is causing the X axis drive chain to go wonky.
Power supplies are where I would be looking. Without a CRO this gets a bit tricky. Set up your system with that spiral test program (a good idea, btw) and monitor the various power supplies on the BoB and on the drivers as it runs.
Btw, that 4.25 V - that sounds wrong. Either 3.3 V or 5.0 V would be OK, but not 4.25 V. You may need to try an external PS on the BoB.
Cheers
Roger
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Hi Inferno
Oh, things are not that bad. There is usually more than one bug, and you have dealt with the first one.
Zip tie - hilarious! Gowachin Law: first exonerate the judge. Ah well.
likely that the problem is that the computer can't communicate properly with that many steps at the same time.
No, I do not think that will be the solution, not at all. That is not how Mach works. I think you should assume that the right pulses are coming out the PP. From memory, EPP is the right setting. Also remember that when you exercise the X axis only, it works perfectly.
These are all steppers? If so we can discount encoder noise.
I see two main possibilities: pulses are being lost going through the Bob, or the drivers are missing some pulses. But the loss is most likely due to the extra load when you go multi-axis. Something is causing the X axis drive chain to go wonky.
Power supplies are where I would be looking. Without a CRO this gets a bit tricky. Set up your system with that spiral test program (a good idea, btw) and monitor the various power supplies on the BoB and on the drivers as it runs.
Btw, that 4.25 V - that sounds wrong. Either 3.3 V or 5.0 V would be OK, but not 4.25 V. You may need to try an external PS on the BoB.
Cheers
Roger
I was mistaken about the 4.25
It's actually 4.45
That's splitting hairs.
I checked the USB on the BoB and it's reporting the 4.45 so that's where the drivers are getting their voltage.
I checked the power supply on the computer and I can get 12.08 or 5.1v if I hard wire into the power supply.
I'm leaning that direction now. Hard wire.
I'm also wondering if I should switch the drivers from a common positive to a common ground and then set the Mach3 for that in the port settings. I suppose it can't hurt.
I'm really leaning to the USB not being able to supply enough power for the drivers all at once. Especially considering it's 4.45v. Theoretically, if all lugs are going at the same time I could be drawing current on 12 devices. 4 drivers with 3 "devices" each.
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Common Ground - DEFINITELY! I would never run on a common positive, ever. Huge room for disaster there.
Getting a good solid 0/+5.0 supply: YES. Hard-wire - YES.
Now, a thought. The X axis now runs fine by itself, yes? Can you get the Y axis running properly *by itself*? If so, same for Z axis - *by itself*. If so, then the odds of there being a PS problem rocket.
Btw, if you are checking the PS voltage, check it at the PS output AND at the BoB PCB AND at the the driver PCB as well. Do not assume the wired connections are perfect. Advice for the day.
Cheers
Roger
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Common Ground - DEFINITELY! I would never run on a common positive, ever. Huge room for disaster there.
Getting a good solid 0/+5.0 supply: YES. Hard-wire - YES.
Now, a thought. The X axis now runs fine by itself, yes? Can you get the Y axis running properly *by itself*? If so, same for Z axis - *by itself*. If so, then the odds of there being a PS problem rocket.
Btw, if you are checking the PS voltage, check it at the PS output AND at the BoB PCB AND at the the driver PCB as well. Do not assume the wired connections are perfect. Advice for the day.
Cheers
Roger
Good thoughts. I will go there next.
I just swapped out to a common ground and flipped the standard in the port setup.
I also hard wired to the Computer power supply.
I checked voltages and now I get +4.5v at the driver (direction pin and enable pin) when it's engaged. That should be more than enough to ensure a "good" signal.
Same results, if not a little worse.
During all the different tests, I get weird voltages all over. At one point I found 2.2v
I think it's time I mapped this out.
I will isolate the X then Y then Z to see if one of the steppers is giving a weird feedback.
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X isn't working right now when isolated. There goes THAT test.
It's odd because when I jog the stepper I can see that the direction will switch back and forth when jogging without me touching the other direction. For instance, I jog clockwise a few times and it might make three jumps clockwise and one jump counterclockwise. ONLY when I jog it though. If I hold down the key to move it it will sometimes jog backwards for about 5 steps (7 degrees) and then go forward.
The Y axis and Z axis displayed the same symptoms.
As part of the above test, I switched around the coils and rain on just a single set of A/B. It didn't change the symptoms
I also flipped the polarity of one coil to see if it changed anything and it didn't.
There's something weird here.
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I do NOT think 4.5 V is acceptable.
I am a long way away and I do not know, but I suspect you might have a bad or loose connection in the power supply chain. I have seen loose screws, broken wires, and even the terminal block screw bearing down on the insulation rather than the copper in one case.
In the power supply lead to a power tool I found a completely broken conductor - deep inside the cable. Gave me hell for a while.
Cheers
Roger
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I do NOT think 4.5 V is acceptable.
I am a long way away and I do not know, but I suspect you might have a bad or loose connection in the power supply chain. I have seen loose screws, broken wires, and even the terminal block screw bearing down on the insulation rather than the copper in one case.
In the power supply lead to a power tool I found a completely broken conductor - deep inside the cable. Gave me hell for a while.
Cheers
Roger
Let's table that thought for a second. I only say this because
I FOUND A NEW SYMPTOM!!
Sorry, but I got a little excited.
When jogging with the ctrl key I thought I was doing something odd like not waiting enough time between steps so when it missed a step I didn't think much about it.
But there's a pattern there.
Using the X-axis alone, I discovered the pattern for the skips is as follows (1 being a step, 0 being a missed step)
011010110101101
That's a pattern of FIVE in a dual coil system.
My brain says it should only be 4 or 8 in a pattern, not FIVE.
So, once I figure out why it has a FIVE step pattern, I think I will be on to the solution.
I did test this over and over and came with the same pattern. This will explain the missing and jumping steps.
Any ideas?
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Absolutely no idea at all. It makes no sense to me.
Personally, and this is just simple me you understand, I would focus on the power supply.
Cheers
Roger
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I've ordered an oscilloscope but it won't be here for a week. I plan on using it on the power supply and the stepper signals.
I've checked power in just about every area I can with a multimeter and get no discrepancies along the way.
The 24v power supply has the same numbers across all the drivers whether under load or not. If there's a weird signal there, I won't pick it up til I get it on the scope.
The only weird thing I see at this point is the 4.5v signal when I am supplying 5.1v but it's less odd when I was getting 4.45 when only supplying 3.3v. I suspect it's a regulated signal to be @4.5v.
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Where is the 4.5 V? If it is on a rail, very strange. If it is on an output, fine.
If it is on a rail, can you identify the convertor chip, and is there a small adjustable pot nearby?
Cheers
Roger
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Where is the 4.5 V? If it is on a rail, very strange. If it is on an output, fine.
If it is on a rail, can you identify the convertor chip, and is there a small adjustable pot nearby?
Cheers
Roger
The 4.5 is on the output.
As near as I can remember there's no pot on the board. I'd look but ended up with a lap parasite (neighborhood cat) keeping me from playing with the board.
EDIT
Parasite detached. There are no pots on the board. A total of a dozen resistors only. No way to adjust the output voltage without knowing which resistor to remove and what value to install.
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Progress but no progress.
I found the reason the pattern was what it was. It was simple math.
I had my tuning set at 600 steps per inch. That means that the program needed to drop two steps out of each five to maintain the .001" accuracy that's built in by default.
I set the tuning to 1000 steps per inch and it now jog-steps one step at a time with no missed steps.
Then I ran my g-code file and checked and it lost accuracy again. So there's still the original issue. It drops steps or, rather, reverses some. And it seems to do it on slow steps only.
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Reversing some steps?
That sounds as though the driver is not sequencing properly. It should step through a phase cycle in a uniform manner, but if it misses a step or two it can appear to reverse briefly. This is especially possible near resonance.
It would be interesting to beg, borrow or even buy a Gecko 203V stepper motor driver, and to test the system with it. These drivers WILL work properly. The owner of the company has a famous published guarantee: if you can blow it up he will repair or replace for free. All he asks is that you keep the metal swarf out of it! Afaik, there have not been many claims on the company.
Cheers
Roger
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Hi,
Roger is right, no matter what BoB or even external controller you use or even the steppers you use you'll need good drivers. Even if all the other components are prefect nothing
good will happen unless you have good drivers and Gecko are consistently rated the best. They are not cheap, howvever you only buy them once. Other experienced CNCers on the forum
recommend Leadshine AM882 and can be had for under $100.
Note that both the top line Geckos and the top rated Leadshine drivers are rated to 72V and 80V respectively, that's not a typo. To get the best from your steppers you should be planning to have a
power supply (evevntually) of 60V or more. You simply MUST have high voltages if you wish your steppers to run at moderate to high speeds...don't buy bull********* 50V drivers get the real deal from
the get go.
Craig
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I'm not discounting what you guys are saying. I just don't have a way to test it yet. That's why I have the oscilloscope on the way. I can't keep throwing money out there looking for the problem. Once I have it checked with an oscilloscope I will know what's what.
Until then, I tinker. LOL
Also, when I say it appears to back up, it can back up 10 steps and then flip forward again.
I also need to check to make sure I have the coils in the proper sequence. You'd think that if I had one of them flipped then it wouldn't turn at all but who knows at this point.
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I do want to add in that I'm using drivers that are very popular (yes, I know, price and all) and am having a hard time believing that I have 8 bad drivers.
I've also used 3 different BoB's from 2 different sources and have a hard time believing I have 3 bad BoB's (although admittedly I may have burned up the first two but I doubt it based on the knowledge I gleaned while figuring things out).
I KNOW my cable is good now. I know I have a full 5V power from the PC cuz it's hard wired now. There's still the possibility of the 3.3v signal coming from the PC causing problems. I have a parallel port expansion card on the way with the oscilloscope.
And, yes, once I get the whole thing figured out I will buy a beefier power supply. I don't have an unlimited budget so I have to take baby steps. Once everything is built, I will upgrade the components as this will, hopefully, be a money-making venture in the long run.
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I think I'm going to connect an LED to the direction pin to see if it's switching when the motor is hiccupping. It's not definitive but could tell me something til the scope arrives.
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when I say it appears to back up, it can back up 10 steps and then flip forward again.
ULP! That is NOT what I was talking about!
It suggests the Dir line is flapping around. Can you stick a LED on that line and watch it while you move the X axis slowly (F=10 mm/sec)? You may need to attach it at different places, like out of the PP, into the BoB, out of the BoB, into the driver.
Yeah, I'm confused too. Time to tinker. I do remember one time when everything was utterly confusing. It turned out to be a problem inside a connector. Fwiiw. I had to take the covers off the connector to find it.
Just a thought, which may or may not have any effect: could you put a 1.5 kohm pull-up resistor on every motor output at the input to the BoB? 1.5 kohm, 1/8 W or 1/16 W resistors.
Cheers
Roger
(More fun than a midnight movie.)
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Just a FWIW, it really, really, really is not a good idea to export power from the PC - it likes to live in its own little world inside its steel box :) A decent 5v 1A SM PSU is a couple of ££ at most, you should have the BOB and drivers powered by that and use the PP to run the opto-couplers on the BOB inputs alone, no need for a USB then, USB sucks.
It does sound like you have issues with the DIR signals and if you do then you will have issues with the STEP signals too which could = your problems.
I had a bad BOB, a good one too, it would work fine on a 9v battery (built in 5v regulator) but not a PSU - tore my hair out for weeks on my first plasma with this, in the end they replaced it and away we went - this was from a good UK supplier, not eBay etc, it was not a cheap BOB - just shows that even good stuff can be bad out of the box.
The fact you have ordered a 'scope shows serious intent here, but if it were me, I would likely have binned the bob and started again on a different make - it really is the king-pin in the system.
Can you not go ethernet UC300eth etc?
Ethernet rocks for machine control as its noise immune and reliable.
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I do agree with Dave about going ethernet (UC300 or ESS), except that I am curious as to why the current system misbehaves this badly. Chuckle - that is of course an academic interest!
It may be the BoB, but I still have some money on connectors and the PS distribution. I would definitely like to see a separate external PS for the BoB - common earth to the PC of course.
Cheers
Roger
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- common earth to the PC of course.
I disagree here ;) I would NOT common anything to the PC - just let the parallel port operate the opto-isolators on the BOB inputs under their own power, the BOB should not care how or where the opto LED's get their juice only that they go on and off correctly (3.3v/5v etc) The BOB circuitry should have its own PSU.
Don't forget PC's are rarely earthed - they usually float just above supply earth/ground by a small resistor in the PSU, grounding the PC case is a death-wish on a plasma machine :) I know this is not plasma BUT what goes good for the worst process in CNC (plasma) is generally bullet-proof for anything else so it's a sound example.
Isolation from PC to machine is vital - this is why they fit opto-isolators on BOB's :)
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I looked up the specs on my computer today and was shocked that it only has a 200w power supply. What a piece of junk.
I was reminded of a problem I had with a computer about 12 years ago. Whenever I went to print I would have to turn off a peripheral or the computer would lock up solid. The company had a dozen of these computers and all of them died within a year or so. All were bad power supplies.
This makes me wonder if it's as simple as that. Maybe the 3.3v is enough for my BoB but the 3.3 is tapped when more than one signal is sent. Worth a thought anyhow.
Tonight, since I don't have the oscilloscope yet, I will connect leds and maybe pullup/down resistors to see if anything jumps out.
I can also, probably, dig up a 5v power supply and isolate it from the host computer.
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OK, earthing. A topic all in itself!
My PC is thoroughly earthed. Australian Standards require that, and they are very good standards.
My whole system is also earthed to the same Earth point - every bit of it.
Electrical isolation between PC and CNC for all signal lines - YES. This can be optical, which is very good and I use a lot of it, but remember that Ethernet devices are also isolated from the Ethernet cable: they are transformer coupled.
So - full signal isolation, PS grounding, CNC frame grounding, and lots of screening everywhere (screens to ground).
As for the PC power supply - sigh. You will have to monitor for a bit. External PSs are always recommended.
Cheers
Roger
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Ha, I saw "earthling".
So, I tried the LED test. The LED doesn't blink as if it's getting a cruddy signal.
I thought I'd try some other things while I'm waiting for the Oscope and haven't found a 5v supply yet.
First. I get 4.8v at the signal pins to the driver. It appears consistent via the LED and the multimeter which, admittedly, are both flawed in their functions.
Then I thought I'd go into the motor tuning and play with the velocities to see what happens when.
Here's where it got fun.
I set the velocity at "1", but the program saved the velocity a hair over "1", and was able to single step the motor perfectly. It did, however, make noises while holding certain steps.
Next I thought I'd set the velocity to 50. When cycling the motor it was a VERY loud motor.
When I set the velocity to 45 the motor hops around. It's back and forth all over the place.
At 100 the motor runs smooth.
So, something causes the motor to freak out around the 45 steps per second mark.
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I found a 5v power supply and disconnected the PS from the computer.
I common grounded (earthed) everything.
No change in the results.
This is compelling.
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When I set the velocity to 45 the motor hops around. It's back and forth all over the place.
At 100 the motor runs smooth.
At first glance, that sounds like resonance. It can be a real pain.
Simple (cheaper) drivers cannot handle this. You need a fairly sophisticated driver to do so. It can take a significant amount of processing power to suppress the resonance.
You MIGHT be able to reduce the effect by adding a 'damper'. A solid disk on the motor shaft, coupled to the shaft via something very lossy might help. Plasticene, Blu-Tack, double-sided foam tape, are all possibles. None of them last very well though.
Cheers
Roger
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When you say resonance, are you saying electrical resonance or mechanical?
I ask because the motor does that even with a load on it.
I should shoot a small youtube video of it.
If I set the signal to low side the problem persists but is reduced.
I'm looking around for a 4 wire stepper to see if I get the same effect on a 4 wire.
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It's an electro-mechanical resonance (just to be difficult).
Energise the motor somehow. It will go stiff and hold its position.
But now apply some torque, and the shaft will rotate a bit. That is a spring.
When you have a mass and a spring, you can get bouncing or oscillation. If you drive the system near the right frequency, it can hit resonance and oscillate wildly. So can any other mass/spring system.
Cheers
Roger
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A video is worth a thousand words
https://youtu.be/5s0y1Pj-8JM
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Resonance imho.
Try at 1/5 speed, or at 5x speed.
Cheers
Roger
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Works fine at anything under 40 or over 55.
But it HAS to accelerate past 45 to gt to anything over 45 and it always messes up on the acceleration.
I tried to buffer the possible resonance with my finger and thumb giving various levels of stability and the motor is VERY persistent on making the steps as you see in the video.
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Yup.
It's a hard world: you have four choices:
Hope that the assembled system (ball screw etc) will damp it down enough
Figure out a mechanical damper (no-one else does this)
Stay below 45
Buy a new driver like a Gecko 203V
Cheers
Roger
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Yup.
It's a hard world: you have four choices:
Hope that the assembled system (ball screw etc) will damp it down enough
Figure out a mechanical damper (no-one else does this)
Stay below 45
Buy a new driver like a Gecko 203V
Cheers
Roger
OR, I could get new stepper motors.
I just hooked up a 3A (using my driver set to 1A) 6 wire stepper motor and it worked flawlessly.
I'm thinking these are just weird motors.
I'll do more testing tomorrow but it seems like the motors just don't like to work "normal".
I have a couple other motors that aren't like the other 25 so I will check them also.
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If you run a 3 A stepper at 1 A, the 'spring' is much weaker. You may manage to avoid a significant response, especially once you have a toothed belt & lead screw hooked up onto the motor. If you run them at 3 A there will probably be a resonance.
I have a drawer full of old round steppers, including some quite expensive large ones. They were inherited for free. Their design relies on some ferrite magnets. Trouble is, over the years the ferrite magnets have lost their field strength, so the motors (all of them) are now gutless wonders. The pain of accepting that was high :'(
Cheers
Roger
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Well, if all the steppers I have are dead then they're dead. I wasn't going to use them for the final project anyhow. I can still use them as generators for a water powered light show (if I ever get around to that project).
I had intended on using new steppers anyhow so might as well get it done.
I'm still going to do the whole oscilloscope thing and I'm going to step my driver up to 3 amps on the working motor to see if I get hinky results. After all this is all a learning process for me.
I know I have another new stepper out in my garage so I will test that one also. It's connected to a balls crew already which is why I haven't used it til now. It's pretty bulky to play with.
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After all this is all a learning process for me.
Oh, it is that for ALL of us!
Keeps me out of my wife's hair, anyhow.
Cheers
Roger
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Resonance?
I took the 3 amp motor that was working fine on one amp, and hooked it up to 3 amps.
It suffered the same symptoms as the 1 amp motor at one amp.
So... resonance?
How do I keep my new steppers from not doing this?
I'm going to play with underclocking.
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There are several ways to deal with resonance - I think I mentioned this earlier.
* Never go near it (stay slow)
* Try to make a mechanical damper to fit on the shaft (negligible likelihood of success)
* Try to damp it down with a toothed belt and a lead-screw (with LOTs of prayers)
* Buy a modern driver which includes electronic resonance damping.
* Use a bi-phase sinewave drive rather than steps. This may or may not succeed, and is almost the same as using a modern high-order micro-stepping driver anyhow.
Cheers
Roger
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There are several ways to deal with resonance - I think I mentioned this earlier.
* Never go near it (stay slow) It happens at a very slow speed
* Try to make a mechanical damper to fit on the shaft (negligible likelihood of success) Then I won't bother with it
* Try to damp it down with a toothed belt and a lead-screw (with LOTs of prayers) Then I won't bother with it
* Buy a modern driver which includes electronic resonance damping. In time, in time....
* Use a bi-phase sinewave drive rather than steps. This may or may not succeed, and is almost the same as using a modern high-order micro-stepping driver anyhow. Then I won't bother with it
Cheers
Roger
In the meantime, I'm going to play with multistepping and/or underclocking. It's possible that my drivers are over amping. I don't have a way to test that.
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Multi-stepping is your best chance.
Cheers
Roger
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Multi-stepping is your best chance.
Cheers
Roger
So far multistepping gave the most promising results.
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I did some reading and watching of YouTube videos and have a better understanding of resonance and I am convinced my problem is just that. Resonance.
Now I will be exploring the various methods of removing the resonance factor.
Thanks for pointing me in the right direction.
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I wouldn't do too much work if you are not keeping these motors - it will all change with new motors and certainly with new drives ;)
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I wouldn't do too much work if you are not keeping these motors - it will all change with new motors and certainly with new drives ;)
Point taken.
Anything I do with these motors now is to gain a better understanding of things. I'm not looking for a solution, per second, but more of a path to a solution.
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So, I'm looking at new components to purchase.
(I should start a new thread but this will suffice for now)
The stepper motors I'm planning on using are:
Dual Shaft Nema 23 with rated 439oz.in torque
Full Step Angle: 1.8° (200 Steps)
Rated Current per Phase: 3.5A
Holding Torque: 3.1Nm
Resistance per Phase: 1.1ohms
Wiring Configuration: 4-Wire Bipolar
Nominal Rated Input Voltage: 24 V, 48 V
Actual Rated Input Voltage: 24-48VDC
Power supply:
Wide Range 100-240V AC-DC 600W 48V12.5A
High efficiency, high reliability, low cost.
High 600W power to fit more devices.
Wide range of input voltage support, both of 100-120VAC
200-240VAC input voltage are available(Adjusted By Switch)
Adjustable approx 40-52VDC Output Voltage support.
PWM control and regulation, insure the steady and precise output voltage.
Built-in a powerful fan for cooling.
Built-in EMI filter.
100% full load burn-in test.
Over current, over voltage, short circuit and overheat protections.
Low output ripple and yawp.
Connected with either 16/4 wire or more widely available 18/4 wire.
I will be installing it all with aviation connectors from the control box to the motors.
This should give me the best, solid, system.
After all is assembled and I have a working machine (even if it has bugs) I will update the drivers and controller.
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Hi Inferno
Frankly, I would prefer to first update the drivers, then the power supply, and only at the end would I look at the motors themselves. But that is just my bias - partly due to the fact that when I did finally update the drivers, everything else worked so much better.
Cheers
Roger
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Hi,
I strongly support what Roger proposes. By far and away the weakest link you have is the drivers. Replace those with good ones you may well find everything else
is good enough, and no matter what motors or powersupply you use is ever going to make up for poor drivers.
I use Vexta 5 phase steppers, 5 phase is somewhat esoteric but they have a few advantages. When I first got them I used a homemade, home design driver, quick and nasty. I was
somewhat disappointed at the motors particularly as I paid a real PREMIUM to get good quality. Eventually I bought the genuine Vexta Drivers that are specifically intended for these motors,
they have an open circuit voltage of 150V!. They are absolutely superb, they spin my motors at 2400rpm all day and have not missed a step in four years. Without those drivers the motors
are really very average.
Craig
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I understand what you guys are saying and if finances worked that way, I would go that way.
I don't need a perfect table at the get go. I need proof of concept. Once I have proof of concept I can justify adding funds to the project. Any upgrades, that take funds, before proof of concept will delay the project.
The drivers will be easier to swap out than the motors will which is why I decided to do motors first. The power supply is something that I know isn't adequate for the proof of concept.
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Hi,
this is a capable driver:
https://www.ebay.com/itm/Leadshine-AM882-Stepper-Drive-with-Sensorless-Detection-Up-to-80VDC-8-2A/121235083471?hash=item1c3a2c90cf:g:Gd4AAMXQOT5Q~Sn9 (https://www.ebay.com/itm/Leadshine-AM882-Stepper-Drive-with-Sensorless-Detection-Up-to-80VDC-8-2A/121235083471?hash=item1c3a2c90cf:g:Gd4AAMXQOT5Q~Sn9)
Try one and see, you want a path to a solution, this is a path...
Craig
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Hi,
this is a capable driver:
https://www.ebay.com/itm/Leadshine-AM882-Stepper-Drive-with-Sensorless-Detection-Up-to-80VDC-8-2A/121235083471?hash=item1c3a2c90cf:g:Gd4AAMXQOT5Q~Sn9 (https://www.ebay.com/itm/Leadshine-AM882-Stepper-Drive-with-Sensorless-Detection-Up-to-80VDC-8-2A/121235083471?hash=item1c3a2c90cf:g:Gd4AAMXQOT5Q~Sn9)
Try one and see, you want a path to a solution, this is a path...
Craig
Thanks for the link. I'll have to wait for an Ebay 15% day and then place an order. (They've been having a lot of those days lately)
I think it might be a good idea to buy one and see how it performs compared to my TB6600 based driver.
FWIW, the current driver still loses steps even on 800 microstep setting. It just seems to be less actual rotation is missed. Load on the motor or no load on the motor seems to yield the same results.
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Hi,
ditch the TB6660, they are rubbish. Even if you get them to go right the moment you try to decelerate your motor hard the back EMF will blow the driver chip.
Get a decent driver, there are some experienced CNCers who recommend these Leadshine units and plenty more who recommend Gecko.
Craig
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I was looking at VEXTA drivers and it seems I need to watch the ratings on them. The motors I'm going to use will be 3A so I can't be getting a 1A driver.
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Hi,
Vexta make two and five phase steppers, don't confuse the them.
My steppers are 23 size and fitted with a low backlash 10:1 planetary gearbox. Even second hand they were over $250 each and the drivers were another $200 each.
The motors and drivers are matched at 1.4A per phase. With a five phase steppers four phases are active at any given instant. Thus the total current in the motor
is 4.6A. I run them at 1A per phase so they run a little cooler.
The gear reduction means my machine is quite slow, rapids of 1200mm/minute but great torque, the stall thrust through 5mm pitch ballscrews is over 5000N. I got what I wanted but paid
a premium, knowing what I know now I think I could have spent more wisely and still achieved a good result. I would think long and hard before getting five phase steppers, they are good
but somewhat rare and all of them are expensive.
Craig
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I'm looking at these.
https://www.ebay.com/itm/THREE-CNC-Gecko-G-201X-ONE-YEAR-WARRANTY-stepper-motor-Drivers-WITH-EXTRAS-G-201/330679891164?epid=1726495475&hash=item4cfe0eb4dc:g:NtoAAMXQk-FRFA7r
Gecko G-201. They should be able to handle the finished platform. I like that they have built in anti-resonance.
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Hi,
yes very good value for money and Gecko is the leading brand.
Did you note that there is only one resolution, that is to say micro stepping is fixed at 10 per full step or 2000 step per revolution.
This is good in most circumstances but not all. Provided your design is good with 2000 step/rev then go for it.
Craig
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GO FOR IT!
The microstepping thing is a non-event in practice.
Cheers
Roger
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Hi,
by way of a reminder, say you wish your stepper motor to spin at 1200 rpm at maximum speed, that is 20 rev per second.
With microstpping fixed this would mean the driver would need to be pulsed at 20 X 2000 =40,000 or 40kHz to rotate that fast. Mach's standard parallel port is only 25kHz.
You could of course set Machs kernel speed to 45kHz, in fact you'd have to. Upping Machs kernel speed ups the pressure on your PC to perform.
An even better way to resolve it is to use an external motion controller, but they are not free. A good modestly priced controller in the range $100-$200.
Craig
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What Craig said is correct, but maybe it does not matter at this stage. If Inferno can get the machine running correctly, even if slowly, that will be a big step forward, and may be enough to justify further expense.
Cheers
Roger
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Hi,
Roger is right, if you get these things and leave Machs kernel at its standard 25kHz then the maximum speed for the steppers would be 750 rpm and with 5mm pitch
ballscrews that works out to 3.75 m/minute, still plenty damn good!
If you get these things and put a 70V power supply on it whats the bet you will have no need to change your motors, these drivers will make them sing. Whats more they'll keep doing it for years.
Craig
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Thanks again, guys.
I think speed won't be that much of an issue. True my ballscrews are 5mm but they will be on my mill/lathe and that would be plenty fast for that. Those would end up being direct drive with the numbers provided, though. I was intending to set up the long axis with a gear reduction but with the speed being set to what it is, I won't be doing that.
As for the steppers I have vs new ones, on the router table, I want to do the build with the new motors simply because it will be belt drive and not screw drive. The belt drive will need a little more torque than these little 1A motors can provide. It's going to be moving a 2.5 foot (almost one meter) carriage that will probably weigh 40 pounds (20K) on the X axis. I don't want to mess around there. I picked the motors I have based on specs on a machine that moves a similar sized carriage. It's just a CNC knife cutter but the dimensions are similar.
Hearing that the Gecko drives only have one setting for stepping (microstepping) is a little bothersome to me but I'm going with the voices of experience. The worst thing that could happen is I replace them with a different configuration and use them on a different project.
I don't know how much my PC would have to perform to get the kernel to run at 45mhz but it's a clean computer. The only thing it will be doing is running the Mach3 program.
I'm also not above upgrading that as well. In fact, it's part of the plan in the long term.
Keep in mind that everything is low budget to get proof of concept. Not including the CNC table itself, I'm only into this project a couple hundred dollars so far. I do have enough info on the components, now, to know it will work.
I really do wish I could put together an encoder feedback. I know it can be done but that's above my pay grade for a while. Someday, maybe.
Along with that, I eventually want to be able to do CNC threading on my lathe. For that I will need to make sure I have either a stepper driven main drive or an encoder on the main drive. That will be a different learning curve, for sure.
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Hi,
I don't know how much my PC would have to perform to get the kernel to run at 45mhz but it's a clean computer. The only thing it will be doing is running the Mach3 program.
I'm also not above upgrading that as well. In fact, it's part of the plan in the long term
Don't bother upgrading the PC, you'll likely never see the difference, get yourself an external motion controller like an ESS or 57CNC and never look back.
I really do wish I could put together an encoder feedback. I know it can be done but that's above my pay grade for a while
Correctly specified steppers, drivers and powersupply used within their ratings will NEVER lose steps and therefore encoder feedback is a complete waste of money.
My steppers came with 500 ppr encoders already fitted. Once I got them sorted and they haven't missed a step for years I took the encoders off.
The companies who push these hybrid stepper servos are playing on your fears. If a standard stepper is going to lose steps because its overloaded then a feedback stepper of the same
size is also overloaded and will lose steps, the feedback may mean it tries to catch up, but it will fail....its plain overloaded and feedback wont save it, it'll fault 'following error'. Don't waste your
money on these things, learn whats required to have ordinary steppers perform as designed and the limits within which they'll work.
If you want more performance than that go to AC servos, genuine AC servos....not those really expensive Clearpath things....there again another company playing on your fears to print money.
Craig
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I think you underestimate what a belt drive onto a ball screw can do. Do not EVER let any part of your body get in the path of an axis movement. These machines can crush skin and bone without raising a sweat.
I agree with Craig about the rest.
Cheers
Roger
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I think you underestimate what a belt drive onto a ball screw can do. Do not EVER let any part of your body get in the path of an axis movement. These machines can crush skin and bone without raising a sweat.
I agree with Craig about the rest.
Cheers
Roger
I hope I didn't give the impression of ignorance on the strength of belt drives and such. I'm intimately aware of what kind of power I'm looking at.
I've been very lucky in life that my hard learned lessons haven't separated me from my body parts, not that it didn't come close a few times.
I was thinking direct drive with the ballscrew for a couple reasons. Reason one being that one ballscrew is already set up as a direct drive.
I suppose if I had an issue with the axis being too slow (unlikely on the lathe) then I could gear it up instead of down.
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Hi,
all my ballscrews are direct drive. I use those el-cheapo aluminum couplers with a spiral slot in them. They flex a bit
and result in 'lost motion' which is not desirable but what has happened is on the odd occassion where I've crashed
the coupler shears off rather than wrecking the gearbox/stepper/ballscrew. Something like a mechanical fuse.
Craig
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Hi,
all my ballscrews are direct drive. I use those el-cheapo aluminum couplers with a spiral slot in them. They flex a bit
and result in 'lost motion' which is not desirable but what has happened is on the odd occassion where I've crashed
the coupler shears off rather than wrecking the gearbox/stepper/ballscrew. Something like a mechanical fuse.
Craig
I was thinking of using those but maybe something a little beefier than the cheap Chinese ones. I know there are a few styles of the cheap ones though so who knows.
I don't need to buy a new ballscrew every time I make a programming mistake.
Maybe a coupler system like this will work
(https://www.dhresource.com/albu_254058321_00-1.0x0/6-35x8mm-cnc-motor-jaw-shaft-coupling-6-35mm.jpg)
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Those couplers are quite good, provided they are a tight fit over the rubber.
Personally, I would aim for a GT2 belt reduction, but in the meantime ...
Cheers
Roger
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Hi,
yes they'll do fine if there a sung fit. The 'lost motion' due to torsional flexure of the cheap couplers is 4um.
Quite frankly chasing 4um is not high on my list of things to do.
With the 10:1 gearbox my steppers are rated at 705oz.in With a 5mm pitch ballscrew of 20mm diameter that means a
rated thrust of 1480 lbf! I need some sort of mechanical fuse and the wee couplers do the job well, it was not my
intent, it just worked out that way. I don't want couplers such as the ones you've pictured, it would mean a blown
gearbox if I had a crash.
Craig
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Without a gearbox, a crash should just cause the motor to skip.
I think it will be a good idea to design a failsafe element. Thanks for mentioning it. I will put it in the back of my head as something to work on.
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Hi,
I note you were talking 34 size steppers which could easily be 700 oz.in without a gearbox and therefore capable of 1500 lbf
at stall. 1500lbf deserves respect.
Craig
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Hi,
I note you were talking 34 size steppers which could easily be 700 oz.in without a gearbox and therefore capable of 1500 lbf
at stall. 1500lbf deserves respect.
Craig
I've rethought the 34's. I have a plan for 23's with 430 oz/in which is still finger breaking territory.
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Well, I've ruled out the power supply and released the magic smoke from my BoB.
I bought a new 48V power supply and hooked it up. I started the X motor cycling and then ran a G-code.
The stepper dropped exactly the same steps as when using the 24V power supply.
In the process, I forgot my BoB was only rated for 24V through the relay and connected capacitor and, well, a loud POP and the capacitor smoke released.
The BoB still worked with the blown capacitor though. All is not lost on that board. I can always solder on a new capacitor and I have two other boards.
So, different motors, problem exists.
Different BoB, problem exists.
Different Power Supply, problem exists.
Next is drivers but they be spendy.
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Here I am, back at my project after a break to start a new job and fight off a weird, sudden, pinched nerve issue in my back.
Anyhow, I purchased Gecko 201X drivers and tried to hook one up. I'm sure I have a few things wrong because it functions worse than the cheap Chinese ones.
It's jumpy and resonance is insane. And it made my stepper get super warm, super quick. I finally shut it down after about a minute of tinkering.
Much more reading will need to be done before I can feel confident that this is going to work.
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You must be DEFINITELY doing something wrong with the Gecko. They are very good drivers.
So - read on and check. You will find it.
Cheers
Roger
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I do know the first time it was hooked up I had left the dip switches alone and in factory position. That sent 7AMPS to the steppers that are rated at ONE. So that's wy the stepper got hot fast.
Dropped the dips down to the one amp that I need and tried again and the driver started to smell right off. I shut it down and checked the wiring to make sure I have it right. I have it wired right, I assume, based on the manual that came with the drivers.
I also noticed the power supply was dimming like there was a direct short and pulsing about one dim cycle per minute. This concerns me greatly as I noticed the LED on the BoB dimming as well.
I disconnected the positive (Vcc) from the gecko and then turned on the power and the BoB was fine.
I'm going to have to break out the multi meter to check everything before I try again.
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One thing to remember: if you have damaged the Gecko 201X, contact Gecko about a repair. They are very, very good about that.
Cheers
Roger
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One thing to remember: if you have damaged the Gecko 201X, contact Gecko about a repair. They are very, very good about that.
Cheers
Roger
At $100 each, they damn well better be.
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Hi,
if I understand your post you hooked up a motor without bothering to set up the driver per the manual???
Geckos have a great reputation for reliability and you've managed to pop one straight out of the box.
Craig
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Hi,
before you hook up another one confirm the inductance of the motor you are hooking up. Don't guess....get an accurate number,
the G210X will accept motors with a minimum inductance of 1mH. If you try a motor with less, and your little 1A motors could well be less,
the driver may well not adequately control the current and you'll blow the output bridge.
Craig
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> if I understand your post you hooked up a motor without bothering to set up the driver per the manual???
Such is life for the vendor.
That is the joy of the 203V: Gecko claim you can NOT destroy it. But the 201X does not carry that claim. Instead the PDf states:
CAUTION! Do not short the motor leads to each other or to ground; damage will result to the G201X.
CAUTION! Current settings above 3 Amps without a heatsink will result in damage to the G201X.
Cheers
Roger
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Hi,
thinking a little more about the minimum inductance specification and your experiments earlier in this thread with these motors.
If the are 8 wire motors ie 4 pairs of windings and you hook them out of phase then the field of one winding cancels the other and in effect
you have zero inductance, and that will pop your driver for sure.
I think you are going to have to nail that down properly BEFORE you do any more damage. You must devise some test to ensure that the two windings
you are hooking in parallel are co-phase. If I recall you said that these motors are only for experimentation...you plan on replacing them in the real machine?
If that's the case get one of your intended and final motors and DONT LOSE THE PAPERWORK if you don't want to blow s*********t up.
Craig
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I've verified the windings through a few methods as well as reading the data sheets on the motors.
As for blowing the motors, if the manufacturers have a driver that will blow right out of the box by connecting them to motors with a lower amp rating than stock config then they are selling a crappy product.
I know the gecko didn't get hot. I was holding it in my hand. My stepper DID get hot though.
If the supply amperage is the problem then I should be able to take a second gecko and hook it up with the proper amp setting and it should perform beautifully, right? If that's not the issue then it will surely suffer the same fate as the first driver (assuming it's damaged)
At any rate, other than the dip switch setting, I hooked it up according to the manual. What I found interesting is the manual says if I hook it up to a common on terminal 10 it can be 3.3vdc, 5.5vdc or gnd. I find it odd that it can be any of the three without additional jumper settings.
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Hi,
a lower amp rating than stock config then they are selling a crappy product.
Bull*********....its a good product and you are misapplying it. Double check the inductance before you try another one.
Craig
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if the manufacturers have a driver that will blow right out of the box by connecting them to motors with a lower amp rating than stock config then they are selling a crappy product.
I think you misunderstand. If you connect a 1 A motor to a driver set up to deliver 7 A, you might blow the MOTOR. That would be your fault.
If you connect a driver to a motor which has been mis-wired to present zero inductance, then you might blow the driver. That too would be your fault.
I know the gecko didn't get hot. I was holding it in my hand. My stepper DID get hot though.
Holding the Gecko in your hand when it should have been bolted down to a heatsink would also be your fault.
It may be that in this case yo have merely 'warmed' the motor and the Gecko has survived.
If the supply amperage is the problem then I should be able to take a second gecko and hook it up with the proper amp setting and it should perform beautifully, right?
NOT if you have the motor mis-wired.
What I found interesting is the manual says if I hook it up to a common on terminal 10 it can be 3.3vdc, 5.5vdc or gnd. I find it odd that it can be any of the three without additional jumper settings.
Yeah, that is OK. It just means they have a 'smart' front end or interface. Quite reasonable.
Building a CNC actually requires some engineering and electronic skills. It is not something you can easily do by yourself without those skills - despite what vendors might claim.
Cheers
Roger
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rcaffin,
I appreciate all your input.
I held the driver in my hand to assure that it wasn't getting hot, that's all. It barely got beyonc room temp so the heat sink wouldn't have done anything anyhow at that point.
I'm using the same windings on the stepper that I used on the cheaper drivers, that worked flawlessly except that it had the resonance. The resonance is the only reason I felt I needed the gecko drivers as it says they have a resonance buffer (rheostat) onboard to smooth out resonance.
I checked my power supply and it is 48 volts and clean. No reason for the pulsing LED I observed on the gecko or BoB. With the gecko disconnected from the power supply I don't see any pulsing on the power supply side of the BoB.
So, something IN the gecko is drawing the power from my power supply down to zero in a pulse. I'm surprised it's not fused to prevent such things.
Next step is to disconnect EVERYTHING from the gecko to see if it still draws down the power supply when it's only connected to the power supply.
P.S. My heatsinks aren't here yet. I'm thinking of robbing the ones on the other drivers for now.
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I just disconnected everything from the driver and turned on the power supply. No pulsing.
I reconnected the stepper and... pulsing.
I disconnected the stepper and hooked up a different stepper... no pulsing.
I now have a stepper motor in my garbage can.
It seems the 7 amps tot he stepper was more than it could handle. I know at least one winding fried because I did the test to see if shorting a winding would drag the motor and it didn't drag. Winding "A" is toast.
So now I have it all set for 1 amp. The second stepper is connected and testing will continue.
P.S. I am well aware that electrical knowledge and some engineering is involved with making a CNC machine. I'm more than qualified to learn as I go about things I don't know about. The only reason I screwed up the 7 amp thing was because I misread something in the manual. There's a part that says you don't need to use the resistors and they were optional. I then missed the part about using the internal dip switches. The manual covers 3 versions of the gecko and I read a part of one and a part of another.
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THe Gecko lives!!
I hooked up a different stepper with the output amp set to 1AMP.
Everything else was set exactly the same as it was when I was getting the pulsing, after verifying that's what the manual said to do.
I did a quick spin with Mach 3 and the keyboard and it seemed to work fine.
I ran a test G-code and it performed flawlessly. There was no resonance.
At the end of the G-code I sent the motor back to zero and it went there. No lost steps.
I still need to run it through some tuning exercises but I'm confident that it will work fine now.
Next big purchase will be either the motion controls for the table or a set of NEMA 34 or 42 motors.
Thanks for all the input.
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Victory!
OK, at a price, but I think we have ALL paid that price. Fwiiw, I had to strip out and replace ALL the electronics in my CNC in the early days, and it had cost me a lot more than yours. All I kept was the big transformer. I used Geckos for the lot, with much satisfaction.
Photos might be of interest later on.
Cheers
Roger
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Victory!
OK, at a price, but I think we have ALL paid that price. Fwiiw, I had to strip out and replace ALL the electronics in my CNC in the early days, and it had cost me a lot more than yours. All I kept was the big transformer. I used Geckos for the lot, with much satisfaction.
Photos might be of interest later on.
Cheers
Roger
Photos will be provided later on. I'll possibly add a build thread.
So far the price has been reasonable. I have burned up a cheap BoB and a stepper motor. The BoB was CHEAP and the stepper was all but free. I have more than 20 of those left over.
I hadn't counted on the cost of the Geckos and the cost of the bigger motors but the rest of my costs are staying well within my initial estimates. So, all in all, it's all good.
I need to start thinking of a central controller enclosure. An old PC cabinet might be where I will go for that. I think I have one laying around somewhere.
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Hi,
I would use a cardboard box until you have a few hundred hours machining under your belt.
Its amazing how things that you thought were important at the beginning prove not to be so
and things that you'd never considered become critical.
Craig
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This is my setup with three active, accurate, stepper motors running.
(http://www.fernohosting.com/CNC/20180610_184131.jpg)
I've run a test G-code a few times now and it always returns to zero when I prompt it to.
-
Hi,
KOOL!
Craig