I found someone else's post about Interpolation problem on A2100 with BSD4 ( https://www.cnczone.com/forums/cinci...2100-bsd4.html ) and we were having some of the same problems. I was wondering if someone could further assist on the issue. We have an Aroow 500 that cannot produce a good circle. When we started out the RPM/Volts 222.2 so, we followed the instructions in the previous post. It's ability to produce a decent circle did improve but, leaves room for improvement. One thing we were not able to do in the instructions was to get the Kv active gain to 2.0 "at any speed'. I can get it to be real close at any given speed but then if checked at a different speed it is way off. Also, what is the deal with the scales icon button to automatically balance. When I attempt to use that function, The Kv active gain is quite different when going from positive to negative direction on the axis. I was able to get it to be more consistent by entering the numbers manually. One last thing, my Kv adjust is in percentage (% Kv Adjust), should that be at 100%? Thank You in advance if you are willing to share your knowledge with me.