Control Techniques VSD Fault

Hi,

I have a couple of Unidrive SP VSDs running in Open loop mode that have developed faults over the last month. The drive setting "3.48 - Position Feedback intialised" somehow gets turned on and is not editable. Even a factory reset does not reset the position feedback setting.

It has resulted in one VSD ramping up and down uncontrollably given a fixed speed reference, and one trying to run at 0.8Hz both with a minimum speed clamp of 20Hz.

Has anyone else had issues with these drives?

UniDrive SP

Good Evening,
Do you have a encoder connected to the drive or an option module. Its my under standing that if an encoder is detected parameter 3.48 will be set to 1.

Try disconnecting or encoder to see if 3.48 sets back to 1 after a factory reset.
Also I dont think it is necessary to save the changes when doing a factory reset but give a try.

Have A Good Day
Tom

There is no encoder attached to the drive, only a Profibus DP module.

I tried removing the Profibus card and carrying out a factory reset but the setting still turns on again as soon as the reset is complete.