External noise rejection accuracy of servo controller

[Westkite2000]

Hey

I'm building on a DC servo motor controller, but I don't like how well external noise rejection is handled.
What I mean with external noise rejection is, when I move the motor shaft my hand.

How well are your controllers handling this?

I like it to be rock solid around the commanded position. +/- 1 tacho step is okay but I get around +/- 50, which is equal to 4dec.

Does it matter in a X-Y table hook-up?

Please help.
Thomas

[Cruiser]

I'm sorry but I don't think you know what your talking about here !
Noise would be an induced voltage to a signal wire from a power wire, or some similar !
I think what you are refering to is the act of the servo trying to hold position when you are twisting the motor's output shaft. This is NOT noise, although you can hear it !

[The Blight]

He is Danish and English is not our primary language, so it could be a simple mix-up.

[daedalus]

What you describe as noise, is positional error. For a brief introduction to how this is solved look at http://en.wikipedia.org/wiki/PID_control. The motor drive would implement such a scheme to actively reduce the error term despite external forces on the motor shaft.