Messages

1

General Mach Discussion / Re: Motors stalling, losing steps

« on: February 09, 2009, 06:56:46 AM »

Thanks for the suggestions. Your statement, "I wonder if one possible cause of a regularly spaced 'tick' might be the system adding or subtracting an extra step to correct for rounding if the drive ratio is something odd that slowly gets off-step.", has me wondering because the "tick" does seemed regularly spaced. Can you elaborate on what might cause the system to add or subtract an extra step?  Thanks.

2

General Mach Discussion / Re: Motors stalling, losing steps

« on: February 08, 2009, 10:25:15 PM »

I am having almost the exact same problem. Here is what I posted to the Mechmate forum. Some additional things, I am running Oriental PK296A2A motors and using Gecko 203Vs. This is also being driven by an IBM 6221, which has an onboard parallel port. Is there something about the IBM parallel ports that MACH and/or the BOB doesn't like?

I'm stumped. I thought I had a grounding problem, but I've rechecked all the grounds and everything looks good. The symptoms are:

1) If I go very slow, there seem to be no problems, although I do notice an occasional "tick" from the motors.

2) Operating at 300 in/min and anywhere from 5-20 in/sec/sec acceleration, all motors will run smooth, with the normal high pitch whine.

3) They do not get hot, nor do the geckos

4) After traveling for anywhere from 20 - 100 inches, the motors will what I would describe as gear grinding sound and quit spinning. If I stop and start again, it runs smooth again.

5) All of the motors seem to be doing this. At first I noticed it on the X-axis only, so thought it might be a binding problem. I have dropped all motors and still get the behavior even under no load.

I'm guessing software setting or tuning problem, just not sure what exactly would cause this?

Under Mach 3 Config + Motor Tuning, there are two boxes labeled Step Pulse and Dir Pulse with units of micro-seconds? What should these values be?

Thanks