I'm getting "joint following errors" on my Z-Axis when I increase the
jog speed above ~1015 mm/min.
I also see it on X (and presumably Y) when I increase its max speed to
over 2336 mm/min; not quite linear given Z has twice (4mm/rev) the pitch
of X (2mm/rev) with the same microstepping (800/rev).
BTW: I don't use 2336 mm/min in real life (ACME lead screws :-(); I'm
just playing with the jog button in Axis with the drivers powered down
but the Z axis will certainly do a bit more than 1015 mm/min and I'd
like to use that or at least understand why I can't.
It's a stepper based system using a Mesa 5I25 and the standard
BASE_PERIOD of 50us which should allow 20,000 steps per second
(according to TFM). The SERVO_PERIOD is 1000000 (standard).
1015 mm/min is 17 mm/s and my Z STEP_SCALE is set at 200 (4mm pitch, 800
microsteps per rev) so that's 17*200 = 3,400 steps per second which is
well within the 20,000.
I've tried increasing FERROR to silly levels (10), deleting MIN_FERROR
and that doesn't seem to make much difference.
The thing that did make a difference was decreasing the MAX_ACCELERATION
to something really slow like 5mm/s/s, it's normally set at 350, but
playing in pncconf I can get over 40 mm/s with an acceleration of 350
mm/s/s so I don't understand what's going wrong.
I'm obviously being a muppet (what's new?) and misunderstanding
something here. Could one of you gurus help shine some light on this?
--
Regards,
Russell
--------------------------------------------------------------------
| Russell Brown | MAIL: russ...@lls.com PHONE: 01780 471800 |
| Lady Lodge Systems | WWW Work: http://www.lls.com |
| Peterborough, England | WWW Play: http://www.ruffle.me.uk |
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