Now I have Metronix servodrive APD-VS15N and Galil motion controller DMC-4030. As I understand DMC-4030 can operation in speed control, position control and torque control modes (and ADS-VS15N can operation in same modes).
What is the best mode of operation for best responsibility, accuracy and dynamic characteristics of servo system?
Also I need to link 2 axis for synchronous operation (X1 and X2). Is it available in all modes operation? I know that gearing mode is available for all modes but may be in some modes I'll get unacceptable difference between axis' positions which will skew portal?
What constants shall I tune in DMC for each mode of operation?
Later I used Panasonic servodrives with another motion controller in position control mode. But I was not pleasured responsibility of system.
Galil_AndyH on 08/04/2010 - 11:24
The Galil Controller closes a position loop. We update the reference/commanded position at a constant rate to command constant speeds for velocity applications.
If you have a drive that can operate in position, velocity or current mode, choose velocity or current mode. If you run in velocity mode then the KD term will be much lower than if you run in current mode.
Tuning parameters are system dependent. If your amplifier is in velocity mode then you will likely have lower KD values. FV will also be effective in this setup.
Gearing works for all modes of motion. If you are worried about lag, gear off of commanded position, see the GA command for more information.
Fedor Bobkov on 08/06/2010 - 00:49
Thank you for your relpy.
As I understand in torque and velocity modes I shall connect drive to same DMC's output (analog +-10 V output)? And difference (for DMC) between this modes is only in KD value?
Galil_AndyH on 08/09/2010 - 09:18
In both torque and velocity mode you will use the +/-10V analog output.
The MAIN difference (not the only) will be that with a velocity mode amplifier you will not be able to have much KD gain on the controller. But the ALL the PID values will be different from a velocity mode amplifier and a current/torque mode amplifier. For instance, if you tuned for the current mode amplifier and found that a gains of 1,10,100 for KI, KP and KD worked best for your system. The gains of 1,10,0 for KI, KP and KD will likely not work for the velocity mode amplifier, you would need to re-tune the system.
Fedor Bobkov on 08/12/2010 - 23:47
Yesterday I began tune Y servodrive and DMC controller. Both operate in torque mode. After autotune with Galil Tools Software DMC set values: KD - 2379, KP - 304, KI - 10.
During motion I tried to minimize positioning error and adjust values to: KD - 2534, KP - 473, KI - 112.
This is like values that you wrote in this thread later.
Thank you!
Fedor Bobkov on 09/21/2010 - 08:33
Another strange event:
After motion torque value stay not zero. After forward motion it becomes 0.4 V and stay it continuously. After backward motion it becomes -0.4 V. But motor doesn't move at this moment.
Is it normal?
Galil_AndyH on 09/21/2010 - 10:22
Probably mechanical friction in your system. Not necessarily normal, but not a problem as long as your position error is within tolerance.
LeGa on 01/16/2011 - 05:39
You may use standard Gearing mode for synchronous operation of 2 axes as well. But such mode have option allowing using Master axis commanded position (instead Master encoder) for Slave command - see GA CX command. And as have already checked can improve synchronism between axes significantly.