Servo PID Tuning - can't clamp down on overshoot

1. I really don't think this is a problem. We had the acceleration even higher, and it didn't make the problem worse, IIRC. We can check again, though.

2. Possibly. The resolver specs say the excitation freq is 4.5kHz. We have it set at 5 on the 7i49. It is a plain 7i49 model (NOT HV). I don't have a good scope, and just a plain Lowe's Amprobe DMM. Would halscope be able to show anything, and if so, what should I be looking at???

3. I will try to drop the FF2 down. (we only used it this way to try to clamp down on the initial lag, because it seemed to work well in the Gnipsel tutorial - now that you point it out, it makes sense that it is making the overshoot worse.)
ALSO ... the overshoot doesn't really change magnitude much with FF2 = 0, it just oscillates a little less. Even without FF2, there is still significant overshoot.

I will try some variations of acceleration, etc in a little bit and post halscope pictures.

Attached are pictures with maxerrorI with FF2 from before, and no FF2

I don't know why the Igain changes. It is the Igain *PIN*, not the parameter, so I just assumed that it was the actual calculated I from the PID calculations.

Here are halscope shots at 100IPM, with & without FF2 ... ALL at HALF-acceleration (10 in/s^2 ==> ie reaches 100ipm in ~0.17s and 700ipm in ~1s). It doesn't really change that unresponsive lag.

Here are more screenshots

• same acceleration (10in/s^2)
• no FF2
• just dropping P from 20 to 15 to 10 to 5 to 3 (see the file names)

I was able to recenter before & after with Igain after these screenshots, but nothing seems to really help the initial lag at all.

Hmm if accceleration doesn't affect the overshoot then its not likely to be lag in the resolver
mechanical?