I'm trying to use a BLDC motor with a 2000 line count encoder on an AMC BE25A20 drive in encoder velocity mode and can't get it to function properly.

When I use open loop mode everything is fine: I can adjust the speed with a pot on the +ref input from full speed CW to CCW and am able to adjust very fine around the zero speed midpoint.

But when I switch to encoder velocity mode this doesn't work anymore, I can't adjust for low speed. The motor either turns fast CW or CCW, slow speed doesn't work, the motor reverses direction at the potentiometer midpoint at a much too high speed.

I tried adjusting the drive's gain pot's but no luck.

The encoder line count (2000) might be too high, I searched on the AMC site but can't find what the line count should be.

Info or idea's ?

Thanks,
Luc.