Quote Originally Posted by Jonathan View Post
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.
Jonathan.
As you wrote, the problem is the aceleration is too low for me in this case.
I've being palying with Pn216 and Pn217 an with the ramps of my board, but no luck, although Pn216/217 are in zero, the system wont run faster.
Now, you're near my actual problem, it is that the gains Pn100 and Pn102 haven't variations in my positioning graphics. Except that if I move them too differents, I get overshooting or excesive vibration.
What is strange for me, is that I never get more speed while increasing the gain.. why ???, I've being playing with a wide set of values for them, and the motor seems to not change it speed.
Since it is my first experience with this drives...I'm asking to me.... Is there any "Pn or Fn" value that produce the gain is not responding ? Reading the manual in page 239....I'm asking to me in what tuning level I've my Pn170 now.... good point.
You know, first I did the auto tuning, and then, I modified the gains and Pn216/217 while running interactively. But I can't never change the speed position doing that. Except if the values of Pn216/217 are increased and speed goes down (of course).
Next Tuesday, I'll have a tektronix near the machine, or, maybe I will replace the drive for a stepper, to let my customer work with the machine, while I try again the servodrive in my office, with the motor and driver and the oscilloscope under the table.

Thank you so much.