I have a system with 3 Micromaster MM440 drives. They are all supposed to be setup the same and are all programmed the same in the PLC. However, when 2 of these drives are not enabled the display on the drive flashes between 0hz and 30hz. 30hz is the speed reference that is being sent to the drive from the PLC. This reference is always sent to the drive, even when not enabled.
The third drive does not oscilate between 0 and 30hz but it still receives a speed reference from the PLC when not enabled. Any thoughts about what I need to change so that they all operate the same. My customer does not care whether they all oscilate or all show 0hz when not enabled, but they want them all to be the same.
Flashing between 0 & 30Hz (when ever PLC is sending 30 Hz) on the drive terminals is normal. The BOP wants to tell that there is a set point frequency can be read by terminals and the drive enable signal is not energized.
For the third drive, did you measured the setpoint signal using a multimeter?
If there is a setpoint signal and the drive doesn't blinking between the corrseponding Hz of it and 0Hz, then there is something different between this drive and the other two drives.
You can use drive monitor to upload parameters from one of the two drives and then download it to the third one.
Hope this helps.