Messages

1

General Mach Discussion / G41/42 toolpath display only to around 1000 lines?

« on: January 01, 2013, 11:46:58 AM »

Hi Guys,

recently been playing with the G41/42 codes to learn how to apply them to serially produced parts.

Was pulling my hair out for a while as the toolpath display was not showing the White trajectory lines on some of my CAM produced gcode.

I know that there are limitations in the G41/42 callout so I have researched ans stuck to them. What is funny though, once the code was corrected the white trajectory still failed to show and Mach was not giving an error.

If I simulate the trajectory though, the green trajectory tracer follows the line that should be white.

If I half the length of the program, the white trajectory appears.
So I am confident that all is good and that the only issue is the length of the program.

Anyone else seen this?

2

SmoothStepper USB / Re: ESS and encoders

« on: December 16, 2012, 06:25:54 AM »

I think there was a plug in for this but worked on MODBUS using digital calipers.

Well, I can relate to your feelings re: lost steps as I have only recently installed a smooth stepper. Previously I had a Gecko 540 running it but replaced that with 3 separate drivers in an attempt to get more current to the motors.
It turns out the the parallel port was not up to the job really.

With the SS as the pulse train is so stable and accurate, I have yet t notice and lost steps. I can push my mill to around 900mm/min on the rapids under my 6" vise but rarely ever need to go that fast anyway. I don't machine faster than 400mm/min anyway.

My mill has cheepo chinesey double ballscrews on each axis so I get 0.02-0.05mm backlash anyway. What has really impressed me though is that when I compare my Mach3 DRO and my physical glass scales type DRO, they match to within 0.005mm 0.01mm all day long.

Moral of the story: See how you get on the the SS alone before you part with more money

3

SmoothStepper USB / Re: Newbie: issues regarding limits, e-stop and backlash comp

« on: October 11, 2012, 06:11:10 PM »

So having been in contact with Greg, the following has become clear:

The LPT has a different behaviour when the limits are tripped to how the SS handles them. He is aware of the difference and he has the fix on his list but not a priority.

Greg modified the plugin to fix the issue I was having with the e-stop being declared when the limits were hit too. So BIG UP TO THE MAN!

Most of this thread has been to try gain an understanding on how the SS differs from the LPT. Hopefully, it will help others that are making the switch.

Jeff, thanks for sticking with it too.

Now, does anybody have a video of the SS working with backlash compensation? It seems that mine is working when I compare the Mach DRO and the physical DRO on my machine but I do not get the jerk with the change in direction that I have come to know from the LPT.

4

SmoothStepper USB / Re: Newbie: issues regarding limits, e-stop and backlash comp

« on: October 09, 2012, 03:24:52 PM »

Well looks like there is something wrong.

I removed the SS from the machine, put the XML file on my laptop and installed the required plugins.

The BOB was no-where near the SS, only thing connected was a microswitch on pin 1 of port 3( aux I/O)

E-stop declared on port 2 pin 3 but not actually connected.

Just pressing the limit switch MAch returned the limit tripped msg.

Virtually jogged and pressed the limit....same thing I was getting in the other setup. E-stop triggered.

I also installed the revision F of the plugin and got exactly the same response.

So I have eliminated all variables except the SS.


Anybody have any ideas? Do I have a defective SS?

5

SmoothStepper USB / Re: Newbie: issues regarding limits, e-stop and backlash comp

« on: October 08, 2012, 04:11:11 PM »

Tonight I spent a good hour and a half reconnecting my limit switches in series. Now I only activate pin 10 for everything (++. --. home)

To be on the safe side, I rewired the e-stop mushroom button to normally open.

So when the limit switches get tripped, all the input pins should read low. This is what they do.

Tested the limit with machine stationary: mach returned limit tripped
Tested the limit with machine pulsing movements: limit trip for a split second followed by the external e-stop

So basically no change, so it is not the huge current draw, since there is no current passing.

Going to have some food and then see what happens if I connect the switches to Port 3 on the SS directly.

6

SmoothStepper USB / Re: Newbie: issues regarding limits, e-stop and backlash comp

« on: October 08, 2012, 03:56:27 AM »

Jeff,

makes sense. I had disconnected the enable pins and the cables as the SS would flake out every time the drives were enabled. The power to the switches is coming in through the 5V screw terminals and is taken from the computers power supply. Considering that the BOB works even without the 5V being attached, it is taking probably taking voltage through the LPT port pins.

I can have a look at connecting the limits to the auxilary IO's of the SS and see if that helps. Ideally I would be looking at a simpler BOB.

Really just goes to show how flaky the USB is so I am this close to getting rid of the board and going ESS.

7

SmoothStepper USB / Re: Newbie: issues regarding limits, e-stop and backlash comp

« on: October 07, 2012, 12:58:02 PM »

Jeff,

didn't make it clear sorry. I am not using the G540. I recently replaced it with a breakout board and higher amperage drivers and thought I could explain the wiring I have for the limits by referring to the G540 since you are probably very very familiar with it.

As you say, the g540 does have a BOB but I was not happy with the restriction in the rapid speed imposed by the 3.5 amp dirvers.

You have any ideas on the behavior of my SS?

8

SmoothStepper USB / Re: Newbie: issues regarding limits, e-stop and backlash comp

« on: October 07, 2012, 08:30:14 AM »

Hi Jeff,

Please see xml attached. The best way to describe my limit switch connections is the gecko G540 recommendation which you will see in the G540 manual on page 8 of ten.  All the limit switches are normally closed. When the limit is reached, the circuit is broken. see attached photo, (hand drawn)
The only difference is that the pin numbers are governed by my new breakout board.

The breakout board I am using is: http://www.savebase.com/infobase/downloads/Breakout_Board_Stepper_Driver/User_Manual_5_axis_Breakout_board.pdf

I had tried the exact same thing I was doing with the machine, but using the parrallel port (no SS) this morning.

What I would expect, and what does happen when using the lpt:
- you hit a limit
-mach tells you you hit a limit
-you press reset
-mach allows you to slow jog off the limit
-once off the limit mach goes into e-stop and you have to press the reset button

What I get with the SS:

-if I just press a limit switch mach says that a limit has been triggered, which is fine


- if I am moving and hit a limit (even with the motor power switched off so SS is sending signals but not physically moving the machine)
-mach tells me for a split second that the limit has tripped and then says external e-stop requested.
-when you press reset you can jog off the limit and keep going even after the limit switch has been released.
-in the SS diagnostic, the external e-stop does not show as active when the limit is tripped.

Would these phenomena be the reason I do not get the super quick jerk that takes up the backlash? when you jog off a limit in LPT, mach does not do the backlash comp jerk.

I will make a video of the above to make it even clearer.

9

SmoothStepper USB / Re: Newbie: issues regarding limits, e-stop and backlash comp

« on: October 06, 2012, 03:20:39 PM »

Nope...no joy even ground to the case and with the capacitor and resistor removed...

Noticed that Mach does return a limit triggered message a split second before going into external e-stop.

10

SmoothStepper USB / Re: Newbie: issues regarding limits, e-stop and backlash comp

« on: October 06, 2012, 10:56:16 AM »

I have noticed today that when the limits are tripped, mach briefly flashes the limit trip info before going into external e-stop condition


watchdog at 100 did nothing either.

I see that the capacitor and resistor are still on my board. Will get rid of those and report back.