Which frequency for a wiper motor?

I'd like to know which frequency is the best for a wiper motor.
In my setup I use a 22 MHz crystal, and the motor doesn't move as expected. When it is getting close to the requested position and the PWM is getting narrower, the motor stops moving, just whistling, and never reaches the requested position. For example the requested position is the middle point. The motor should move till the pot shows ~512. But my motor stops at ~440-450 and doesn't (or can't) move, although the AMC still sends to PWM to move it further (this is the same in the opposite direction).
I think the source of the problem is the too high PWM frequency as motor can't follow it, but maybe not.
Yes I know, I could try to reflash the AMC with different crystals : , but at the moment I don't have more crystals at home, and I'd like to know what frequencies you use guys with a wiper motor.

Thanks,
Janos

hi,

i think 22Mhz is very good (24Mhz munch error)

i use 22Mhz to..

have you pictures from your frame (wiper motion)??

The frequency have nothing to do with that.... Its the PID that needs calibration!

Change the KP to higher value until it positions itself correctly... Try increase it to 10 or 15. Some said that in some cases they needed to put up to KP 25!!!

That is exactly what should happen with a proportional control.

You will always have a small error with P only, but it will get very small and you won't notice it.

Increase kP as Thanos said to speed up the motor.

Thank you Thanos and Frakk,
I thought that the frequency is too fast to follow, but I changed KP to 10 and now it works as it should, it stops the motor around 512 +- a few, if the required is 512.
I have been reading these forum pages for weeks, but it seems, that it wasn't enough to know all the know-how.

Thanks again,
Janos