Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: WB1 on October 15, 2011, 12:50:47 AM
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Hi everyone!!
I'm having a little trouble getting my motors to work/spin/move.... When I first received my motors/drivers/breakout board I wired them all together and while using mach 3 it all seemed to work.
12 months later I have now finally finished my mill but can't get the motors doing much.
I have been following mach 3 installation instructions but with little success. Whenever I try to jog the machine sometimes I hear the motors (high pitch noise). Other times the shaft does 'spin' but its more like its grinding; very slow and noisey and in only one direction. My limit switches and e-stops all work fine.
I have checked my wiring all seems fine. I've checked to see if I have voltages where appropriate.
Changing the velocity and acceleration slides doesn't seem to have any effect on the motor?
Any thoughts Cheers.
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You say changing the velocity and accel settings don't do anything. Are they staying set where you moved them? Did you know you can test the accel and velocity settings with the up/down arrows keys on your keyboard prior to saving? Steps per revolution set correctly?
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I hear the motors (high pitch noise).
Other times the shaft does 'spin' but its more like its grinding; very slow and noisey and in only one direction
Make sure you have the motors wired correctly, the drive currrent set correctly to start, and that the axis is not binding.
1.post your xml file
2.provide power supply, drive, and motor info
3.describe your machine
RICH
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Hi,
Power Supply: 350W Single 24VDC Output Switching P/S.
Driver: Microstep Motor Driver Series CW230. Set (1/16) Microstep // 1.5Amps
Motor: Nema 23 4 Wire Stepper.
There doesn't seem to be any consistence with what its doing. When your in the motor tuning screen (mach 3), x-axis selected, (steps per revolution: 2000, Step Pulse: 1us, Direction Pulse 0, regardless of what velocity and acceleration quantities, the motor some times makes the grinding noise while other times its just locked itself stiff (can't move the shaft). In fact when I turn the power on to the motors I hear the motor 'locking' itself.
I just swapped the x-axis motor around with another exact some type and the same thing happens.
Y-axis and Z-axis are also not working
The motors aren't attached to the screws btw so binding can't be the issue.
So its not the motor or the wiring (double checked) I'm thinking its something to do with breakout board or the settings in mach 3. The chances of all three drivers/motors are not working is stupid. Something to do with the BOB or software settings.
I will get the xml. file to you when I figure out how to do that! :)
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xml. file.
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What BOB are you using?
RICH
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Hi, I don't even know what you would call my BOB but I can tell you its Cheap and Chinese and I'm seriously regretting it.
I have been monitoring the Hi/Lo signals coming from the parallel port as I toggle the motors. The voltages I get from testing from Pin 1 to Pin 2-7 are all correct (Hi signals). But after I plug in the parallel cable into the BOB Pins 4/5 no long show a Hi signal. Pin 4/5 are the Y-axis Step and Direction signals, respectively. Its as though somewhere/somehow its shorting to GND in the BOB.
I'm starting to think I might be look at getting one of those G540 Geckodrives. Anybody got anything to say about those????
On a separate note I was thinking about putting an encoder on each axis but I don't know whats involved in wiring one up. I'm assuming you wire it through the BOB or is there some sort of driver needed for that as well???
Cheers.
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Good grief WB1.
How in the world do you expect someone to have a look for what is wrong with your setup with a reply like
I don't even know what you would call my BOB but I can tell you its Cheap and Chinese
. ???
RICH
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OK OK your right!
But the thing is I really don't know. I have all the documentation in front of me and the best description of the BOB I can give is: DB25 Isolated CNC Breakout Board.
Ok I bought it on ebay over a year ago and it seems they are still selling it:
http://www.ebay.com.au/itm/CNC-DB25-Breakout-Board-MACH3-KCAM4-EMC2-6-axis-New-/260734436913?pt=AU_Business_Industrial_Industrial_Supply_MRO&hash=item3cb4fbc631#ht_2573wt_1413 (http://www.ebay.com.au/itm/CNC-DB25-Breakout-Board-MACH3-KCAM4-EMC2-6-axis-New-/260734436913?pt=AU_Business_Industrial_Industrial_Supply_MRO&hash=item3cb4fbc631#ht_2573wt_1413)
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I have been monitoring the Hi/Lo signals coming from the parallel port as I toggle the motors. The voltages I get from testing from Pin 1 to Pin 2-7 are all correct (Hi signals). But after I plug in the parallel cable into the BOB Pins 4/5 no long show a Hi signal. Pin 4/5 are the Y-axis Step and Direction signals, respectively. Its as though somewhere/somehow its shorting to GND in the BOB.
WB1,
Measure the voltage between any of your parallel port direction pins and pins 18-25 (GND). Jogging in one direction, for that axis, should give 0Volts and in the other direction approx 5Volts. If the max voltage you get is 3.3Volts then you may have a problem with that BoB. (Some BoB's are OK with 3.3V but many of the Chinese type need 5V for the opto isolators to work correctly).
Just a thought,
Tweakie.
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WB1,
Test per what Tweakie posted. Remove the BOB, use the attached xml file. See if the motors respond, if they do then try the bob.
Make sure you that the BOB has 5V going to it.
Of course you will need to revise the motor tuning based on your system.
RICH
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Hi, so I've measured what you guys have been saying and I'm getting approximately 0V for a Lo Signal and 3.3V for a Hi signal.
Tweakie when you say If the max voltage you get is 3.3Volts then you may have a problem with that BoB.
I'm taking that to mean the BOB is not compatible with the computer? Because this was all working 12 months ago.
Do you guys think it could be to do with the length of the parallel port cable? When I had it set up 12 months previously the parallel port cable was only 1 metre long. The cable I'm now using would be approximately 5 metres. Is it possible voltage drop is the problem. I guess I could check the actual voltage coming out of the parallel port on the computer (its just a pain to get to :()
I'll have another look. cheers.
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WB1,
The extra length of cable may just have been the last straw.
Best solution would seem that you need a BoB witch specifically accepts the 3.3V input. There are some to choose from here http://www.cnc4pc.com/Store/osc/index.php?cPath=33&osCsid=671377cb99e791846d6b802f889e5e81
Tweakie.
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Yeah the last straw that was what I was thinking. The voltage coming out of the back of the computer parallel port is 3.375V the exact same as whats coming out of the parallel port cable. But of course voltage drop only occurs when you have current flowing so I can't really compare the two.
I'll try a couple more things next but I have some questions.
So is 5V or 3.3V the standard for Hi signals on the parallel port?
So a geckodrive G540 doesn't work with 3.3V?
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Just tried moving my computer closer to the BOB and used the shorter parallel cable with RICH's xml. file. Nothing new; motor is locked stiff no movement. I've tried jogging in the motor tuning window and I've tried jogging by pressing 'tab' and using the jogging window.
I'm running out of ideas damn it! ???
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So a geckodrive G540 doesn't work with 3.3V?
It's made to work with both voltages.
So is 5V or 3.3V the standard for Hi signals on the parallel port?
A lot of the new computers are 3.3 volts, some are dual voltage, can buy dual voltage cards , usualy there is a switch or jumper on the card
to set the output volatge. Have a look in the Mach3 Manual about Logic signals .
PC cords are usualy limited in length and you will / may have problems if they are long. Even in industry wiring signal length is limited at higher voltages
but amplifiers are used when needed but not deisrable.
Did you try the motors with the BOB removed? Is the reset button flashing?
RICH
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Thanks for that info.
You say that some parallel port cards you can change the output voltage? I guess thats not possible if the port is built into the motherboard?
Not sure about what you mean by:
Did you try the motors with the BOB removed?
The motors won't move if the BOB isn't plugged in ??? I think I'm missing what your saying....
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WB1,
If it is a voltage issue, which I suspect it is then .......
The Geckos will work OK at 3.3V it's the input side of your BoB that is having the trouble. Replace the BoB with one that accepts 3.3V input signals.
Tweakie.
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Yes this is what I will most probably do. Everyone seems happy with their Gecko drives!
Thanks for your help!
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Hi to anyone that was following this thread. To conclude, I bought a G540 Geckodrive from Ebay for approximately $270 AUD delivered. Besides it taking almost three weeks to arrive, (USPS seem pretty useless!) the G540 has worked like a charm. I followed the setup guide on the Gecko website. I wish I had bought this drive in the first place.
One thing I have noticed is my motors get quite warm/hot. I believe this is because of my 24VDC power supply. But a short term solution I have found is to keep your e-stop tripped. Firstly its safer. And secondly, although your motors aren't moving they have 'holding torque' which essentially means the motors are still 'working' and will heat up if left. If you just hit the e-stop you will hear the motors stop their high pitched noise. Thirdly, if your mill is in the garage, don't use it when the weather is really hot.
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Good to hear you got it working well.
Steppers do get hot, its the nature of them as they are always working even when still. As long as you can still hold your hand on them for a bit then they are probably not too hot. If they are getting hotter then it could be you have the current set to high, not sure how the G540 sets current but with the other Gecko drives you need to set it with external resistors.
Hood
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Hi the current set resistor I used was a 3.3k ohm resistor. My motors are rated to 3A per phase. According to the G540 gecko drive instructions you multiply the 3A by 1000. So I am using a slightly larger resistor which might cause a slight reduction in motor performance, but at the moment I am just happy to see some progress.