Light Machine Corp. Benchman XTr (retrofit)

Today there was a series of successes on PID tuning the BenchmanXT. Error on the xyz are down to 0.0001". This can be improved, but decided to move on. After lunch, I decided to move on to working on the spindle, which has produced frustration. Since the Allen Bradley Ultra 100 drive had input-1 set to torque-mode-selection, I am assuming the original machine was configured in torque mode. I tried one method of increasing FF0 until it produced a stable RPM, then increase I until it hits the desired RPM. It did not work as expected. At a commanded 100rpm, the spindle would not break static. I turned by the time I got the spindle to break static with a commanded 100rpm, the result was over 700rpm. After a few hours of messing around with the numbers, it was time to try moving on to a traditional PID tuning. FYI a small amount of P and I go a long ways. If you are reading this before attempting to tune your spindle, be cautious and start out VERY LOW and work your way up. This time the idea was to start out with a little higher rpm, 500rpm. Once P was high enough to stabilize at ~500rpm, the commanded 600rpm ended up making me shut it down because it started to accelerate to very high numbers. After a while of trying these out for a bit, it was time for a break and ask for some advice. If anyone of you have manually tuned the spindle in your BXT, please give up some tips!
Thanks,
MAC

Don,
Can you help me out with some of the variables in this post? I understand PID, SPU. But was does Int Range mean? Is there a term in the .ini file that this relates to? Also, is the Accel of the spindle 50deg/s^2 or 50rpm/s?
Thanks,
Mac

Your axis error of 0.0001" is what the machines left the factory with.

I don't ever recall having to tune one of those spindles. I inherited the spindle/spindle drive combinations for the XT line and wasn't allowed to change anything until the 45K, 50K spindle options and drive obsolescence issues required it.
If I recall correctly, the only time we used the drives in torque mode was for rigid tapping applications (low RPM), it should have been in velocity mode at all other times. However, with that being said, it has been a long time since I was hands deep with an XT spindle so I could be completely out of it.
I don't recall the specific details of the terms in the .ini file and my attempts to contact the software guru for the Benchman product line have been unsuccessful.
Not much help, I know.
Sorry
Don

Mac,
On checking my information, I do have a copy of the parameter (.PAR) file used by the Ultra-Master software for this spindle motor (dated 2005). I cannot open it without the Ultra-Master software which I cannot run on any machine I have. (NT was the last version I knew worked). Contact me if you want it and I will send it.
Don

No, it is unintelligible with text editors, but I also have the Ultramaster S/W if you need it (also limited to NT). It may work with XP, but again, I have no way to verify.

It is a 5KB file.