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Author Topic: Jerky motion...yes I've read the other posts :-)  (Read 14815 times)

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Offline Hood

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Re: Jerky motion...yes I've read the other posts :-)
« Reply #20 on: July 04, 2008, 05:38:57 AM »
Meant to say I was in CV mode (G64)

Hood
Re: Jerky motion...yes I've read the other posts :-)
« Reply #21 on: July 04, 2008, 02:09:46 PM »
Thanks a lot, I really appreciate it. Now I know what kind of noises they make. I just assumed if it was running prefectly you wouldn't hear the fluctuations in the motors they would run smooth, but now I know. Have a good weekend.

Offline Hood

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Re: Jerky motion...yes I've read the other posts :-)
« Reply #22 on: July 04, 2008, 02:18:57 PM »
My motors do run smooth, the sound does vary however as you can hear, that is normal.
Hood
Re: Jerky motion...yes I've read the other posts :-)
« Reply #23 on: July 04, 2008, 06:28:42 PM »
I've read this and a few other posts with great interest and wonder if anyone can help me with a similar problem. I run a shopbot cnc router with mach latest download lock down and an Ascension controller for the past 2 years quite happily. last month we started to stall motors and it progressively has gotten worse. We have replaced basically everything except the motors now. New PC swapped with old, another new controller swapped, updated software, optimized PC's, replaced all cables including parallel cable, motor cables, connectors all soldered gold contacts, added back up power supply/conditioner, checked voltage at P/S and gecko drivers, verified incoming voltage, added new ground rod and new ground wires isolated from main power supply which is 380V 3 phase main. experimented with rapid and acceleration speeds/setttings, dialing up and down from a low of 100/10 to a high of 600/12, verified pulse settings at 5/5, restored systems, grabbed old and new xmls from back up files, ran tests as airt cuts, with and without rack and pinions engaged and with actual material under torque.

I've discussed with the Ascension designer/developer, exchanged many e-mails with BBarker THANK YOU Brian), and many other friends each familiar with either stepper motors, electrical engineers, proficient cnc users, mach users, and softwere folks all around the USA for the past 3 weeks.
The problem is MOTOR STALLS, growls,and stops on all, some or one axis under low or no load intermittently but with increasing regularity to the point of being totally useless.

When I dial speeds down, growl is diminished db level or seems to vanish but motor cant take any load and stops,, when I dial up, motor growl returns proportionatly with increased ramp and/or rapid and stalls under low or no load almost immediately (3 to 10 seconds)
My historical rapid speed was 425IPM, accel at 12, and a rather slow programmed cut speed generally between 160 and 200 IPM in plastics, foams, and wood stock.
My settings were always the same and all was well.

Folks at shop bot tell me steppers never fail, others seem to agree much less 3 at the same time and I'm dealing with a PULSE issue from parallel cable to Geckos but need an oscilliscope to really find out whats up.
If I do find some odd pulse wave forms, what would that tell me? and what would i do about it? I may have the opportunity to get to a scope next week.

PS voltageĀ  isĀ  at 65+V to PCB and geckos (I think 35V?) and I'm told those look right by other users of the same equipment and motors
Since everything has been replaced except the motors it seems its down to software/settings or motors.
My pulse driver test does not show a flat line but rather a series of hash marks from small to large in the shape of a triangle rotated -90 degrees consistently and repeatedly aross the screen with occasional single line spikes usually small but occasionally up to 80.

We have monitored task manager and see 90% CPU capacity at idle and nothing else runig from the 13 active system/utilities running.
Now if I take motors on cables, run mach, and move via arrow comands, motors growl within about 3 seconds after the key activation and simply stop with a continued growl until I release the command key.

Any ideas?

I've sent xmls, swapped xmls, tried the alternate mach driver test, and followed ever recommendation I've thought of or received to no avail.
After all this and many many conversations most folks feel its our power so I brought the set up to my home shop with cables and motors same condition.
All input is appreciated as we try to recover from 4 weeks now of zero production, tons of replacements, and effort, much help fom friends in the cnc community, with no forward progress.
Is it time to order/replace motors or what could cause this? More importantly, whats the fix?
Thanks
Thanks

Offline Hood

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Re: Jerky motion...yes I've read the other posts :-)
« Reply #24 on: July 04, 2008, 06:43:23 PM »
Can you post a screenshot of the drive test? Have you tried the optimisation steps?
Hood
Re: Jerky motion...yes I've read the other posts :-)
« Reply #25 on: July 04, 2008, 11:28:38 PM »
yes we have optimized. havent figured out how to attach to this forum but I'll research how till I get it posted.
I might have to post to my web site to accomplish this
Thanks

Offline Hood

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Re: Jerky motion...yes I've read the other posts :-)
« Reply #26 on: July 05, 2008, 03:12:54 AM »
if you use the full reply option rather than just the quick reply you will see additional options down at the lower left side. Click on that and you can browse to the file you want to attach.
Hood
Re: Jerky motion...yes I've read the other posts :-)
« Reply #27 on: July 05, 2008, 08:14:08 PM »
best I can do is a word documenbt with comparison of what we believe we should see and representation of what we do see. Am trying but when I select file from browse button, there is nothing getting attached? and no key /instructions on how to attach it to this note?

Offline Hood

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Re: Jerky motion...yes I've read the other posts :-)
« Reply #28 on: July 06, 2008, 07:54:34 AM »
The pulse looks bad but from what you say the average is its not really so bad. I dont know what to suggest as you seem to have done all, one thing to check however is you have the enhanced pulse enabled (General Config page)

If that doesnt help I think I would be stripping things down to the very basics and just set up a new xml with 1 axis and E-Stop, then keep adding the axis one at a time and then limits etc. Hopefully you will be able to run at the basic fine then as you progress you will find the problem.
Hood
Re: Jerky motion...yes I've read the other posts :-)
« Reply #29 on: July 06, 2008, 11:59:51 AM »
Thanks for trying. Have enhanced pulse and tried many other things like replace keyboard, mouse, and assorted changes as well as reverting to older xmls but to dat, the pulse stays the same. So I reinstalled on the P, same results and same pulse graph. Tried completely purged alternate PC with new mach install, different pulse stream (not better, just more irratic than constant) but same results oon motor growls. Seems this has progressively gone from intermittent to now constant. Either immediately on keyboard move or max 2 tyo 3 second delay then growl from motor.
I'm running out of options and beginning it must be the motor but everyone says its highly unlikely to be the motor much less all motors.
Not sure what it is but so far progress is negative.
Thanks again and I hoe this never happens to anyone else. Its a real head scratcher and terribly frustrating. :(