PID parameters

Hi
I really appreciate the responses and good advice. As mentioned I am a new user of EMC2. I have a Bridgeport series II and upgrade the control to EMC2 using a mesa 5I23 and a 7I33. I connected the first axis and encoder and it worked. But when in g code command the speed exceeds from 2000 mm/min following error occurs. I think the PID parameters (or other parameters) are wrong.
I attach my ini file. Can anybody tell me about error in my parameters?

A simple approach to tuning the PID loop with Feed forward component is:


set all parameters to very low values ( say 1 )
increase P untill axis starts to oscillate back off P till it no longer oscillates.

increase FF to about 1% effective contribution

increase D till axis start to hiss ( the mtor will emit a kind of hissing sound )

Increase I untill axis is no longer sloppy but fights back any motor shat displacement you try to make.

This is a good starting point.
Now gradually alter the I and D till loop response is with minimum overshoot and minimum delay.

Try increasing P and FF and optimising the I and D coeffiicients

Presence of FF helps to bring the loop into as good a state as possible so that the I and D components have minimum contribution to make to overall performance.

Zig wrote:

increase FF to about 1% effective contribution

Which FF? And this means that the FF should be (for example) 1 if P is 100?

Good question..
there are a number of feed forward coefficients available to the user.
The simplest and easyest to comprehend in terms of oop beaviour is the simple proportional feed forward. That is to say take one percent nominaly of proportional signal and feed it directly to the servo drive.
This tends to pre correct the loop controller and places a smaller demand on the PID portion of the controller.

So in this case FF0 is the one to play with.

Again no hard and fast rules; use halscope to monitor the actual error

I'll try it. Never used FF0 so far, only FF1 and sometimes FF2 (which both need very small values otherwise the loop becomes very unstable, from what I've seen and read)