In further investigation, it shows the PLC was slowing the drive down. The yellow line trending down shows the Base Speed on a slow decline. We found that we were having more communication issues. The drive was getting down to 17.0Hz and just sticking there. It wasn't going any further, despite the PLC showing that it was sending smaller numbers. I've wired the speed reference to the rewind to be analog from an analog output.
However, I'm having some more issues. My analog seems to have lost its mind. The dancer, despite being scaled to 0-4095 (12 bit), jumps to like 15000+, and is showing up as erratic. If I go and move the dancer by hand, it showed a smooth curve from 0-4095. I moved it from one input to another, same thing. I changed the scaling to 14 bit, cycled the PLC from run to program and back, and then it showed me 0-4095. I put it back to 12 bit, and I'm getting negative raw numbers. Putting a meter on the input, I never see negative numbers. It's even hooked to a programmable signal conditioner that only puts out 0-10V, so I'm having hard time believing that it's the physical input.
What could be causing me this issue? Anyone have any ideas?