Quote Originally Posted by btxsistemas View Post
I'm sending pulses with a board of my design. That board apply aceleration and desaceleration ramps, although, you can avoid them using Pn216 and Pn217 parameters of the drive.

What I see, is: in that low quantity of pulses, I get a very low speed of turn, but,..... in example if move about 1200 pulses, then I get a positioning time about twice as the 25 pulses I get. That's what is getting me crazy.
I strongly need more and more instant aceleration, that the drive don't give me.
From what you've said there it does sound like the problem is the acceleration being too low, as otherwise moving 1200 pulses would not be much different to moving 25.

Have you changed the Pn216 and Pn217 parameters? It seems they are used to smooth sudden changes in acceleration, so if the time constant is set too high that will stop the motor accelerating fast enough. I would try setting both these to a lower number (but not so low as to make the motor stall), perhaps zero, and stop your board applying acceleration/deceleration ramps. If that works you can enable the acceleration setting on your board and gradually increase it to make the motion smoother.

If that doesn't help you could try increasing the proportional gain a little. The motor speed is determined (partially) by multiplying the proportional gain by the position error. Since you're only commanding the motor to move 25 pulses, the position error is quite small so unless the gain is high the motor speed will be quite low, resulting in a slow response. The problem is you may get too much overshoot.

Section 6.5.3 in the servo driver manual, page 239 looks useful...

Do you have an oscilloscope? If so you could use it to measure the actual response time accurately.