I have a Kflop that sends the step and direction to Viper200 drives.

Last night I had finished tuning the machine and all motors were running smooth and didn’t rebound backwards slightly once the job command had been stopped. But I turn it on today and both X & Y axis are rebounding slightly when the command stops. Why is this happening?

When I say rebounding I mean, I hold down the job command in the positive direction, when I let go of the jog command, the motor comes to a stop and then goes into the negative direction a few degrees. Sometimes it’s more obvious than others, sometimes it’s not visible. I worked on this all last night and adjusted the Kp, Kd , ki and loop commands in the viper and then adjusted the P-I-D in the Kmotion and got it to stop, then I saved the settings to my initialization file and it was working fine when I tested it before I turned it off.

Is adjusting the PID in both systems causing interference? It was working fine last night when I turned it all off. And come to think of it, ive had axis randomly start to do this and stop doing this during other on/off cycles.
Could it be a issue in the power supply or somewhere else or in the software?

Has anyone else had an issue with the motors rebounding once the jog command is let go?
Thanks for the insight.