Another servo tuning

and open loop with
MAX_VELOCITY = 100.0
MAX_ACCELERATION = 300.0

at 3000mm/s and 6000mm/s 
now since I don't know where the ferror comes from in this case I kind of have no idea what this measurement tells me. I guess I would be happy if this was actual encoder to cmd difference.

myval wrote:

now since I don't know where the ferror comes from in this case I kind of have no idea what this measurement tells me. 

If all you have done is take the pid loop out, but have left the encoder feedback driving joint feedback, then the f-error calculation is exactly the same as it was before. 

So it is looking like running the drive in position control mode gives much better results. 

This isn't unlikely, the internal loop in the drive can run faster and is therefore likely to be tighter. 
 

At full bore the exe is missing steps. Test setup was dial indicator on one end of full travel open loop and if I run across full lenght few times I get still 0 on dial indicator but fair difference on encoder about 0.02mm on 10 runs. 
Just did the test at 800mm/s well bellow the max for exe and it was spot on.

so yeah the result for future generations do not run EXE box over its max input frequency.

but I would be guessing that the closed loop should be able to compansate for the wrong value. Unusable for machining but I guess I still should be able to set up servo not to overshoot as it is over and under shoots on accel decel.
 

So Andy if I understand correctly change from:
net x-pos-fb <= hm2_7i95.0.encoder.00.position
to this:
net x-pos-fb <= hm2_7i95.0.stepgen.00.position-fb
leaves the f-error calculation from the encoder position?
well this is strange since f-error remains the same dial indicator shows 0 but the encoder count increases slightly every test run.

I am going to have head explosion

myval wrote:

I am going to have head explosion

We need proof ...

Will send you a pic soon. I am just falling in a bottomless hole. I think this tuning is bit over my head.

I found replacement for EXE box which runs at 500Khz at least one plus point.