I have a Galil DMC-4143 connected to a Pacific Scientific PC834 servo amplifier. The amplifier is configured in torque mode and connected via the standard +/10-volt analog command interface. I have read the Galil application note 5420 and setup the drive as described under the torque mode control section. I have also been through of the Galil online tuning tutorials.

Physically, my setup is just a small Pacific Scientific servo motor connected to a THK ball screw type actuator. I can get smooth motion with small values of KD, KP, and KI = 0.
However, increasing KD past about 100 causes oscillations. And I can only set KOI= 1 once KD gets to into its unstable range around 100, otherwise setting KI = 1 causes large (2� of travel) oscillations.

I tried using the �autotune� feature, which results in *really* small values of KD & KP, with KI =1.
I don�t seem to be able to impart any set of values that results in a usable system. Which makes me wonder if this is a tuning issue, or something more fundamental. Any guidance appreciated.