Tuning Problems

[babinda01]

Hi Guys
I am having issues trying to tune in a mill with INDRAMAT servo drives with Brushless DC motors (original fitment). MPU11 and Centroid software(latest version). 2048 Pulse encoders.

The trouble I am having is that I am gettin a lot of high freq oscillations in my motors. Even if I put my "P" very low - .001, I get what I would normally expect with such a low P value, a relativly slow even ocillation almost like a sine wave on the plot, but this sine wave is very "furry" (made up of these oscillations) . And then as I tighten my P value the sine wave slowly goes, but leave these very high oscillations, which leaves my DRO fickering about + - .01mm.

I have just retrofitted two other mills, but I used new AC drives and th,ey tuned up perfectly, but because of the size of this machine we decided to leave the original fitted motors and drives.

Reading the manual there is a set of parameters (324-331) to deal with the "Axis boxcar size" I have played with these values but get no change at all.

Any help would be greatly appreciated.

Andrew

[CNC-Global]

Andrew,

Can you please tell me your Kp Ki values.....I assume that you run the indrament Drives in velocity mode
I will try to help you.

Aamir