Prototrak Plus Retrofit with Mesa 7i77 & 5i25 cards

many thanks for the links and thoughts, Andy!!

After reading more about 2nd loop, my thinking is to make shore I have tried all combinations 1st. Attached is a better trace for the heavy axes "y", I think the correct pins are referenced in the scope trace elements, ""listed as: pid.y.error; pid.y.output; encoder.01.velocity; jount-vel-cmd""



Is the thinking is to have as much "of the other 3 trace" as possible under the "joint-vel-cmd" trace. With as small amount of "encoder.01.velocity" as possible, to push past. What am I looking for in the trace? All suggestions are welcomed.

many thanks for all the help!

In your hal scope plot you will want to increase the gain on the pid.N.error so that you can actually see what is going on. You are looking for micron sized errors. So your current gain setting of 2 (inches?) per division is all but useless. So select channel 1 (your pid.y.error) and slide the gain slider up until the error spikes fill the screen.

Your goal is to minimize those errors and get the encoder velocity trace to match the joint-vel-cmd as closely as possible. More FF2 can help some with your error spikes during acceleration/deceleration.

Many Thanks!

I have worked on these for a while, the "encoder.00.velocity" trace is as close as I have seen to tracking the "joint-vel-cmd". Does this look acceptable? jog feed is 60"/min. I can see the slower the feed the less chance for error.





I tried FF2 all the way to 10; P all the way to 9000; I & D to 90. I will try more if this is not close enough or there is more tuning to do.

Many, many thanks!!

No, not there yet. You want the pid.N.error to be as close to 0 as you can get it all the time. You don't want that to follow the velocity command.

In the attached screen shot notice how the following error never is more that about +/- 0.0015 (that or better is what you are after.) More P (if it doesn't make it unstable) more FF2 (until you start to see too much overshoot).

Thank you, Todd!!

You reference, +/- .0015 this is at the bottom of the hal screen in line "= 0.00126"(ddt 0.04830) is this correct?

Thank you

Yes, If you click on the trace number button at the bottom of the screen, then hover the mouse over the trace, it will show you the values for that point on the trace there at the bottom of the screen.