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Author Topic: motor feedback option in plugin  (Read 2511 times)

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motor feedback option in plugin
« on: March 30, 2011, 02:13:56 PM »
I have a PCI 1842, AMC analog amps ,DC brush servos with tach. I use glass scales as my encoders. I don't seem to have the hunting problem everyone Say's you get but I do have some kind of a motor position error.
When a program first rapids it would seem that the machine doesn't quite make the mark in any random axis. After the next couple of moves it catches up. It might be off .005" of as much as .050" I have found that by checking the use Ref position not encoder for position feedback that the problem goes away. However when I hit reset, my DRO no longer works and I loose position because of slight motor movement when shut down. Any way to get my dro to work in this configuration? or any suggestions on how to fix the position error with the box unchecked?
Re: motor feedback option in plugin
« Reply #1 on: April 02, 2011, 03:16:55 PM »
I have a PCI 1842, AMC analog amps ,DC brush servos with tach. I use glass scales as my encoders. I don't seem to have the hunting problem everyone Say's you get but I do have some kind of a motor position error.
When a program first rapids it would seem that the machine doesn't quite make the mark in any random axis. After the next couple of moves it catches up. It might be off .005" of as much as .050" I have found that by checking the use Ref position not encoder for position feedback that the problem goes away. However when I hit reset, my DRO no longer works and I loose position because of slight motor movement when shut down. Any way to get my dro to work in this configuration? or any suggestions on how to fix the position error with the box unchecked?

I'm also having position-loss problems at the moment, but whilst trying (everything!) to sort it out, I did find that having KI=0 in the PID motor tuning (in the Galil) can cause something similar to what you are getting. My system often settles on KI=0 when autotuning- might be worth checking your tuning in galiltools or smarterm...