General Help

Hi all,
Still floundering with the PID tuning...
Please find attached my .ini file and screenshot of results for X axis.
5i25 + 7i77

I've gotten the following error (blue trace) as flat as I can get it with the values indicated for PID etc. On the tuning tutorial I mentioned above, at 5m/div their line was flat and I can't get close to it. Any suggestions...??

The tutorial plot is probably in inches, since you are in mm, your errors will appear 25.4x larger
(5m/div is a 5 milli-millimeter/div or 5u per division)

On their tutorial...
gnipsel.com/linuxcnc/tuning/servo.html
their halscope is also reading 5m/div, how do I work out is they are using inches?

Assuming that they are using inches, does this mean that my following error is acceptable? having never tuned a servo before I'm unsure as to what level of error to expect.

There's no direct way to tell but the velocity is a big hint...

( JTs tutorial shows a velocity of 1 and 1 mm/sec is not
reasonable as a jog speed for most machines but 1 inch/sec is)

I would say your tuning is fine unless you have an ultra precise machine

Great - and thanks for the prompt replies!

My team also did a complete guide (includes wiring, instalation, ... all with 5i25+7i77) here:

www.wiki.eusurplus.com/index.php?title=Category:Tuning

After the center of the page is the linuxcnc part. Maybe it can help you.

Made quite a bit of progress since my last post. Now have all 3 axis moving. X axis tuned pretty well. Limit switches and encoders all working as they should.
But I'm struggling with homing.
I don't have a separate homing switch for any axis so I've configured (PNCconf) the 7i77 to share X min Limit with Home, Y min limit with home and X max limit with home.
Running through the 'Home All' on the Axis GUI it keeps throwing up an error that says the axis (Z) is on the limit switch, even though I have (hopefully) configured it to ignore limit switches during homing.
Screen Shot and ini fill attached.

As always, all help gratefully received.

In homing section of documentation (page 319/711 - HOME_IGNORE_LIMITS) it says to set this to YES if you dont have a separate homing switch. It says to 'case connect the limit signal to the home switch input in HAL'. Can anyone explain what that actually means please??

I got the info from the pdf here:
linuxcnc.org/docs/2.7/pdf/LinuxCNC_Documentation.pdf

LinuxCNC V2.7.13-4-gd440e5b, 2018-05-11

319/711 (actual pdf page353)