Min Ferror & Ferror

I do not understand the position control utility when controlling it drives.

Where do I not understand?

PCW wrote: try replacing all the (per axis)

setp pid.N.maxerror .0005

statements with

setp pid.N.maxerror 0

(where N is the axis)

Hello,

sorry but i try to understand what this change means. Is this only for testing, or should this parameter set to 0 all the time? Does this mean that no more errors allowed or that no more errors are stored for this pin? Most configuration examples that i saw use a value of .0005.

Sorry for my question but i have a really hard time to wrap my head around the Stepper - PID - FERROR and tuning configuration.

No, those are permanent changes.

The pid.N.maxerror setting is not directly related to following error at all but rather
bounds the PID error (difference between commanded and feedback position)
A setting of 0 mean no bounding is applied. This is documented in the pid manual:

man pid

(at the command line)

You can also set the maxerror to say .01 which will work, but .0005 is too small a number for
metric setups. (this is a pncconf bug, it should use different numbers for inch vs mm machines)

The point of setting the pid.N.maxerror is to prevent large bogus velocity corrections if the
host device has large latency spikes, this is not very likely so disabling the bounding is not
harmful on most machines.

The problem with pncconfs default setting of .0005 on metric configurations is that this is only
a 0.5 micron error which allows only a .5 mm/second correction velocity so you can run out of
correction headroom (for timebase differences for example) on a fast machine

Thanks for the explanation.

I use a MESA 7i76e, Lichuan Closed-Loop Steppers (LC57H380 + LCDA357H) and ballscrews on X and Y with a pitch of 10 and was not able to get higher speed than 8 m/min.

After changing the pid.N.maxerror value to 0 i am able to go up to 14 m/min and propably even higher.

Are there any advantages if i set the value to 0.1 or is it ok to let it disabled by the value of 0?

There is a slight advantage: basically it make the system more robust with regard to
dropped packets or host latency spikes. I would use .01 mm since this is large enough
unless you have broken clock on your PC