Trying this again for the second time, no more attachments, only a google
photos link. I really mean it this time.
https://photos.app.goo.gl/xMK4Ep69i1SpznC58
Here are some halscope screenshots. Would saving the halscope data and
distributing that be better/prefered? Not sure what the policy is here.
This isn't really revealing much to me. All the index-enables fire,
commands go to zero, feedback goes to 0 and then the PID.y.output takes
off, PID.y2(linear).output eventually catches on and doesn't do anything
to help, seems to add fuel to the fire instead of acting in an opposite
direction it should.
Please see screenshots, any thoughts are appreciated.
-Dave
On Sat, 25 Apr 2020 14:44:54 -0400, Peter C. Wallace <p...@mesanet.com>
wrote:
On Sat, 25 Apr 2020, David Berndt wrote:
Date: Sat, 25 Apr 2020 14:21:45 -0400
From: David Berndt <ber...@uberwin.com>
To: "Enhanced Machine Controller (EMC)"
<emc-users@lists.sourceforge.net>,
Peter C. Wallace <p...@mesanet.com>
Subject: Re: [Emc-users] Encoder reset on homing to index
Thanks for the feedback Peter.
I took the time to re-order my hal file (it's a bit of a disaster with
all the other non motion going-ons in there).
Here is the relevant start of m addf's
addf hm2_5i25.0.read servo-thread
addf motion-command-handler servo-thread
addf motion-controller servo-thread
addf pid.x.do-pid-calcs servo-thread
addf pid.y.do-pid-calcs servo-thread #rotary
addf pid.y2.do-pid-calcs servo-thread #linear
addf pid.z.do-pid-calcs servo-thread
addf pid.a.do-pid-calcs servo-thread
addf pid.s.do-pid-calcs servo-thread
addf sum2.3 servo-thread #pid.y.output
+pid.y2.output -> 'y-output' -> hm2_5i25.0.7i77.0.1.analogout1
addf hm2_5i25.0.write servo-thread
I excluded all the stuff below which is are things like servo amp
ready, amp fault, coolant, spindle speed, spindle amp draw, f-error
tracking, stuff that happens in servo-thread but isn't exciting or
relevant to motion in a realtime way.
Yes, PID.y.index-enable, pid.y2.index-enable,
hm2....encoder.03.index-enable, and hm2...encoder.01.index-enable are
all plumbed up and I show them going TRUE during homing.
When I went out to the cold mill this AM and started fooling around I
noticed I was getting some following errors even in my previously
configured "acceptable" config which was driving axis.1.motor-pos-fb
from the rotary encoder still. Some hal-scoping around shows that maybe
with the change I need some re-tuning at higher speeds.
The need for retuning made me think that perhaps if the tuning was
questionable and that lead to a bit of runaway condition at higher
speeds then perhaps if I just decreased the max speed and tried
assigning the linear encoder pos fb to axis pos fb I might see an
improvement.
So I did that, and it did. I'm now jogging back and forth at half the
old max speed and doing some basic G-code tests with the linear axis
being axis.1.motor-pos-fb. Which is nice because the GUI displays more
enjoyable numbers.
I'm not sure which change contributed to what, HAL reorder/cleanup, or
tuning.
My homing situation hasn't really changed. I still have to home twice
to get a completed homing cycle. I once got persistent runaway after
homing (caught quickly by f-error), but it wasn't self correcting,
turning the machine on again (f2) just led to another immediate
runaway. Restarted linuxcnc to try again and all was well. Interesting
problems.
So as it stands now, homing (i have no idea what to actually
try/change, it's broken but also kind of fine...) , and more tuning
(assuming it's not a fools errand to change tuning with the addition of
a linear scale...) are my next steps.
-Dave
I suspect you will have to track down whats going on with halscope
(triggered by index-enable going low) and monitor the commanded
position, feedback position
and PID output
On Sat, 25 Apr 2020 09:44:14 -0400, Peter C. Wallace <p...@mesanet.com>
wrote:
On Sat, 25 Apr 2020, David Berndt wrote:
Date: Sat, 25 Apr 2020 03:23:20 -0400
From: David Berndt <ber...@uberwin.com>
Reply-To: "Enhanced Machine Controller (EMC)"
<emc-users@lists.sourceforge.net>
To: "Enhanced Machine Controller (EMC)"
<emc-users@lists.sourceforge.net>
Subject: Re: [Emc-users] Encoder reset on homing to index
After a few more hours tonight putzing around with this thing. Here's
where I'm at.
I've wired up the shared index. It completes both the encoder's
index-enable cycles. encoder.NRotary.position and
encoder.nLinear.position both reset to ~0. Home is also at 0 as is
homeoffset, so once index is found there should be no need for the
axis to move. However it takes off and gets caught by a fairly strict
ferror.
If I then home it again the result seems to be close enough that the
small post-index-enable completion jump is within f-error. The axis
moves a few .001" and settles. I'm not sure what's causing this jump
in the first/second homing. Because of the ferror the first homing
attempt does not actually complete the homing cycle, ishomed is not
set.
For the homing thing, I may setup a mux to turn off the
pid.yLinear.output. Maybe leave it off until everythings homed, or
everythings homed + some time, or some other benchmark. My machine
spends very little of it's time in an unhomed state and the control
tends to stay on 99% of the time so homing/rehoming isn't really much
of a priority. Or maybe abandon indexed homing.
It would also be nice to be able to feed pid.yLinear.feedback into
axis.1.motor-pos-fb. But that's a recipe for the axis taking
off/tripping ferror instantly. I'm not sure why, I can watch the
pid.yRotary.feedback and pidyLinear.feedback and they're quite close
to each other. I think this works fine pre-homed and breaks after
homing but I'd have to re-run that experiment to be sure. Seeing the
machine @actual position being off a few thou is really
disconcerting. I can always press the @ to switch to machine
commanded, which is (hopefully, if the linear is more accurate) much
closer to reality.
-Dave
Is the index enable signal wired to both PID components in hal?
Also What is the thread order?
(it should be hardware_read, motion, PID, hardware_write)
Peter Wallace
Mesa Electronics
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Peter Wallace
Mesa Electronics
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