Motion Control and Motor Drives

cancel
Showing results for 
Search instead for 
Did you mean: 

PCI-7344 servo tune results in high frequency noise and erratic behavior

I can't seem to get reliable behavior when using the servo tune panel in MAX with a PCI-7344, a Maxon brush motor and a Trust automation TA-115 amplifier.  When I initialize the 7344 to the default "servo" settings in MAX, it sets values of 100 and 1000 for the proportional and derivative gains, and also sets the "encoder polarity" to active high for A, B, and index, and the "encoder index reference" criteria to inactive and active for A and B, respectively.  With these default settings, I can go to the 1-D interactive panel and get reliable, quiet jogging in both directions in "velocity mode".  The step response for these gains isn't terrible, either (attached image).  The problem arises when I select "automatic" tuning and select "auto tune".  Sometimes, the result will be a nice step response, but sometimes the result will be high-frequency noise and vibration in the motor.  After this happens, I can attempt to jog the motor again in the 1-D interactive panel but high-frequency noise and vibration are the only response I get.  To recover, I must select the "servo" default settings and reinitialize the controller.  I haven't found any correlation between encoder polarity (or any other) settings and this autotune behavior.  Does anyone have any advice?

 

 

 

Download All
0 Kudos
Message 1 of 4
(5,090 Views)

Brian_J,

 

My advice would be to tune the motor manually in your case.  The auto-tune function, while extremely helpful at times, is not meant to be applicable to every controller/drive/motor combination.  I would suggest referring to this KnowledgeBase article on the topic of manually tuning your PID.  Let me know if you have any other questions.

Zach C.
Field Engineer
Greater Los Angeles

0 Kudos
Message 2 of 4
(5,075 Views)

@ZachAttack wrote:

Brian_J,

 

My advice would be to tune the motor manually in your case.  The auto-tune function, while extremely helpful at times, is not meant to be applicable to every controller/drive/motor combination.  I would suggest referring to this KnowledgeBase article on the topic of manually tuning your PID.  Let me know if you have any other questions.


The KnowledgeBase article that you reference has a "bad link".  Can you refresh or repair the link?

0 Kudos
Message 3 of 4
(4,993 Views)

My apologies, here is the correct link.

Zach C.
Field Engineer
Greater Los Angeles

0 Kudos
Message 4 of 4
(4,989 Views)