servo accuracy

[footloose]

What is the minimum distance I can turn a servo motor?

Does this depend on the driver, the motor, or both? (I suspect the answer is both, but if someone could explain how, that would be great )

If I want a precise servo setup, should I buy a packaged servo+controller, or can I just use any old servo motor and put a 2500 CPR US Digital encoder on it?

[spoiledbrat]

This depends upon the drive and the encoder. If you have 2500 cpr, 10,000 quad encoders, then the minimum distance is 360 degrees divided by 10,000. That is, 0.036 degrees. However, there are settings within your drive that will determine how stiff (or squishy) the servo will be. That is, if you were to command a position, and then attempt to move the shaft of the servo (by hand) once it is positioned, it will move a small amount. This is adjustable with the drive.

With 250 cpr encoders, coupled to a 0.200" lead ball screw, you would be able to command 0.0002" of an inch movement. That does not mean that you will have 0.0002" accuracy or repeatability. And those terms are a different forum.

Good Luck, and have fun!

Rob