**RESOLVED** oscillation

[Riley]

I'm having a little trouble getting my motors to park when uncommanded. Heavy oscillation occures when I enable an axis. Have gone through the encoder wiring yet again and switched motor leads. With the motor leads one way the motor runs hard in one direction, and with the leads reversed it just jumps back and forth about an inch. Have been trying to adjust the kd but the results dont seem to change. I have been saving the changes between tries. I'm certain that I'm just missing something but it's driving my motors and me crazy. Im running mach with the ajax plugin on win xp.

[diycncscott]

Hello Riley,

While I have some experience tuning the Copely Xenus series, I have not had the opportunity to tune the drives you are using. That said, you may find the PID values I used to be of some help. Please note that I used CNC11 for tuning and I suggest you (and everyone else) use it as well. The real-time O'scope mode is by far the best way to tune. Once you have the PID values optimized for your machine, you can copy the values into the Ajax Plugin Config in Mach.

First thing - Set the Copley drives to velocity mode and SET Kd to ZERO

I followed this process in tuning the Xenus:

1. Backup your CNC11 files by creating a report in CNC11 (F7 -Utilities, F7- Report)
2. Download and install the latest CNC11 software here:
http://ajaxcnc.com/tech/downloads/softw ... /index.php
3. As mentioned, I set the drives to operate in velocity mode
4. In CNC11 I set: Kp = .03, Ki = .001, Kd = 0 and Kv1 = 50

...

[Riley]

Thanks for the info Scott, I now have the x axis holding dead still with a little bit of whining, or singing. I will play with it some more to see how quiet I can make it. This is my first cnc and has become quite a learning experience. Thanks to all that have replied to my posts!

[diycncscott]

Hi Sky,

Glad to hear I was able to help.