What is the possible cause for the motor drift when using NuDrive amplifier?

[Andy30]

We use NuDrive in our PLD system to run a stepper motor controlling a mirror that rasters the laser beam across the target.

We always had a little drift, but after recent shut down of the system it got much worse. The stepper motor visibly moves

when the power and enable switches are on, even though in the labview program it is set to not move. I would like to ask,

what is the possible cause of this drifting? I suspect hardware issue, since the program was running for several years

without any problems. Thank you for help.

[OliviaC]

Hi Andy30,

Is your application running as an open loop program? All hardware do tend to drift over the years and every few years need to be recalibrated. Without any feedback in the program (such as motor position), a drift will show up after some time.

[Brian_Beal]

This sounds like a noise issue.  Can you put a scope on the step input to the drive?