On 7/4/23 18:18, gene heskett wrote:
On 7/4/23 16:49, John Dammeyer wrote:
The problem is under the covers somewhere and the Joint 2 following
error isn't totally accurate but is what happens later.
John
Lets clarify where the error is, because the turn around at the bottom
of the hole is synchronized, the turn around at the top is not.
So where is it when the error was reported?
That reads like the spindle stop time is overly long to me.
Actually the spindle stops so quickly that I can hear the splines
rattle in the pulley driver.
The stop should be so violent the rattle is preloaded to silence.
Do like I've done, add 2 timers in your hal file, one triggered by the
motions direction output, to start when the reverse come in, and is
stopped when the spindle has has stopped as indicated by another timer
set to retrigger for 10 milliseonds on every edge the comes out of the
spindle encoder. The idea it to use this 10 ms lag to indicate the
spindle is slowed enough to be reversed w/o tripping breakers all the
way to the substation, and display the time the first timer is stopped
at in a pyvcp box. I have additional hal stuff to block the reverse from
the spindle control until t is everything but dea stopped, then and only
then do I allow the reversed direction signal into the spindle control,
and the same limit3 then ramps it back up to the chosen speed, with a
mux4 steering the input to the limit3. So the stop is a very fast ramp
down, and the accel ramps it back up to the same speed in the other
direction. 3k max spindle speed fwd to 3k speed in reverse, in under 400
ms. z s/b able to follow that. If not, slow the limit3, giving z a
chance to catch up. That is assuming the following fault is being
blamed on z..
I'm still convinced a lengthy stop is the problem.
Z is following the encoder.
So block the direction change by making a stop out of it until its
stopped, then allow the direction change thru and ramp it back up to
speed. To do that right needs a 4 quadrant control.
Your stepper/servo's may be quite precise, but are they true 4 quadrant
control? IDK, but very few stepper drives we can afford are.
Jon's pwm-servo is, a vfd programmed correctly is. Both can stop the
motor by sucking the spin back out, storing that recovered energy in the
psu's filter caps, then using that over voltage to re-accell the motor
in the other direction and the only problem is the few ms of the
resultant over voltage on the filter caps. The over voltage spike is
there and gone again long before the caps fail short from overheating
due to the leakage at that voltage peak. I think that high voltage pulse
helps to keep an electrolytic formed. Both of my bigger machines are
past due for a 5 year recommended shotgun replacement with no sign of
ageing yet.
You may need to check the addf order in your half file, the basic rule
is that all addf's should be in an order where a single signal coming in
from the machine, should fall thru all processing and go back out to the
machine in the write at the bottom of same invocation of that thread.
Violate that rule and all sorts of problems can crawl out of the woodwork.
We need an analyzer script to check that Andy. Hint hint ;o)>
I suspect that the spindle stops and then starts back in the
clockwise direction too quickly and the Z axis can't do that fast enough.
My spindle is an AC Servo run with step/dir so I could change some
values in the ini file.
[SPINDLE_9]
MAX_VELOCITY = 50.0
#MAX_ACCELERATION = 30.0
MAX_ACCELERATION = 300.0
# The values below should be 25% larger than MAX_VELOCITY and
MAX_ACCELERATION
# If using BACKLASH compensation STEPGEN_MAXACCEL should be 100% larger.
STEPGEN_MAXVEL = 62.50
STEPGEN_MAXACCEL = 375.00
The acceleration values of the spindle are dramatically faster than
the Z axis.
[JOINT_2]
TYPE = LINEAR
HOME = 0.0
FERROR = 0.05
MIN_FERROR = 0.01
# 3.2:1 Max Speed
MAX_VELOCITY = 2.50
MAX_ACCELERATION = 10.0
# The values below should be 25% larger than MAX_VELOCITY and
MAX_ACCELERATION
# If using BACKLASH compensation STEPGEN_MAXACCEL should be 100% larger.
STEPGEN_MAXVEL = 2.75
STEPGEN_MAXACCEL = 20.0
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Cheers, Gene Heskett.
Cheers, Gene Heskett.
--
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