Problem- Z Servo Bumping!!!

[parametric.ms]

I have BOSCH D-6210 Servo Drive with SIEMENS DC Servo Motor on Z axis.

If I make a rapid move there is a clog at first and bumping and the end

There are 3 trimpot on BOSCH
1. OFFSET
2. NOMINAL VALUE (Sollwert)
3. TACHO

What is function for each trimpot? Can I tune those trimpot to fix my problem?Which & How?

Thanks for your help

Andre

[Al_The_Man]

You did not specify what controller you have, but the general rule on tuning the inner loop, which is what the motor/drive/tach loop is, is to first balance the drive (offset),
This is done by preferably disconnecting the ±10vdc analogue control from the CNC and short these drive inputs together. Then tune the offset pot so the motor remains stationary.
Re-connect the drive and make sure the drive is at an in-position point, and tune the Gain, if the drive has one, it could be the nominal value pot?
This should be increased until the motor starts to oscillate then back off around 1 turn.
The Tach pot should only normally be adjusted if you cannot get max rpm from the drive.
The above is assuming it is a velocity drive, i.e. is using the tach feedback.
If you are still getting the bump at start and end, it could be either a mechanical condition or failing that, the PID controller loop may require tuning.
Al.

[parametric.ms]

upps.. I forgot to mention the controller. Its HEIDENHAIN TNC 355.

I saw a few parameter related with PID. But I can determined the perfect value.
Integral Factor, Factor for Difference value,Acceleration.

I'll take a look at mechanical condition first then try to tune PID