Motion Control and Motor Drives

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PID settings in MAX are labeled incorrectly

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I have ignored this problem for years, but battled it again today and wanted input from someone else to confirm the problem.  My motor speed was oscillating so I tried to tune the PID values in MAX interactively.  It is obvious to me that the labels on the PID are incorrect.  The labels are Kp, Kd and Ki, but really show be Kp, Ki and Kd.  To reduce the oscillation the second parameter is increased (labeled Kd, but really Ki).  The last parameter is always 0 (labeled Ki, but really Kd) or it caused problems.  Auto tuning produce 0/3/0 which would make no sense if PDI.

 

This topic from 2006 has a similar problem which was not resolved.

http://forums.ni.com/t5/Motion-Control-and-Motor-Drives/Difference-between-PID-gains-in-MAX-and-appl...

 

Are the labels wrong?  I'm using LabVIEW 2014, Max 15.3 and Motion 15.0 with a PCI-7350.

Michael Munroe, CLD, CTD, MCP
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Accepted by topic author Michael_Munroe

Hi Michael,

 

The labels shouldn't be wrong in MAX; if they were, I'd expect that the context help in the righthand corner would suggest it was the other parameter if that was the case. However, the context help also agrees with the labels. 

 

However, I'd suggest trying to use the tuning software from your drive manufacturer, such as the Kollmorgen Workbench, and then using those values as a starting point in MAX. This article also provides a simple method for tuning the parameters in MAX.

 

Regards,

Regards,

Michael Whitten
Senior RF Applications Engineer
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Your tuning document was very helpful.  It appears the Kd and Ki have similar smoothing responses.  I believe the labels would be correct then.

Michael Munroe, CLD, CTD, MCP
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Hi Mitten! I have an issue with the tuning. Sometimes when I enable the servomotor (I´m using a NI PXI 7354 motion card, a UMI 7774, a servodrive AKD kollmorgen and a kollmorgen servomotor with brake) sometimes the motor star to oscillate even after I do the manual servotuning. I know that I can use workbench to servotune the motor, but, what is the difference, if any, of doing the servotuning in workbench and in MAX?

I think that the oscillations is due the servotuning, but this is something that just started, before that I had been working with the motor normally, without any issue. Can someone help me? Thanks in advance

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