[3.4b3] Homing coupler does not work correctly

Diamondback

@dc42 Hm I'm starting to think that my issue might be related to this thread: https://forum.duet3d.com/topic/25647/3-4b4-and-3-4b5-issue-with-sensorless-homing

If my initial home move command aborted immediately because sensorless homing triggered, the whole behavior makes sense.
I looked at my config and sure enough, C is halfway configured with sensorless homing there:

M574 C1 S3                                      ; Stall detect coupler at low end of its range
;Stall Detection
;M915 C S6 F0 H200 R0                            ; Coupler

(more or less copied from your toolchanger config on github)

I'm not actually using stall detection, but just ram the coupler against its hard stop for some time as recommended.

Thoughts?

T3P3Tony

@diamondback try commenting out the M574 command for C, I also use the "ram the coupler against the hard stop" method on my tool changer. I set the current lower in my home C file during homing and then increase it back up at the end because I want to use more current when coupling the tools than when homing.

Diamondback

@t3p3tony Hm, no luck Still the same broken behavior with no M574 command for C. Maybe there is some default that applies instead?

T3P3Tony

@diamondback what does sending:

M574

With no arguments report?

Also try sending
G1 H2 C-300 F10000
And
G1 H2 C300 F10000

From the console

Diamondback

@t3p3tony said in [3.4b3+] Homing coupler does not work correctly:

M574

It reports nothing for C when nothing is set, so that's good.

	M574
Endstop configuration:
X: high end switch connected to pin xstop
Y: low end switch connected to pin ystop
Z: none
C: none

The G1 commands also work on their own, it's literally just within the homeall file where things go south...

dc42

@diamondback I am having problems homing the coupler on my TC right now, which I am investigating.

dc42

@diamondback please can you try adding parameter R0 to the M584 command that creates the C axis, and reboot.

I am still investigating, however last time I had this problem, it disappeared when I rebooted the controller. So I don't want to do anything that needs a reset, such as trying this M584 change myself.

Diamondback

@dc42 Didn't change anything, with R0 it still homes incorrectly.

dc42

@diamondback please try the binary at https://www.dropbox.com/sh/xeu30go894p9xbs/AAB5U66SH4wbjKIcX0snUbKxa?dl=0. Caution if you are using stall homing: the stall sensitivity on Duet 3 MB6HC changed in release 3.4.0beta5 but has been reverted in this release.

Diamondback

@dc42 I'm afraid I'll need a Duet 2 (Wifi) binary.

dc42

@diamondback I've put one at https://www.dropbox.com/sh/xeu30go894p9xbs/AAB5U66SH4wbjKIcX0snUbKxa?dl=0.

Diamondback

@dc42 I'm carefully optimistic, I couldn't get it to do weird things yet, before it basically failed every single time. Will continue testing...

Diamondback

@dc42 Still no issues with the new binary, seems like you might have found the culprit

dc42

@diamondback thanks, I'll mark this thread as solved.

Diamondback

@dc42 I've been running the firmware build you posted here ever since you did, and no more issues with the coupler! Definitely seems solved!

Diamondback

@dc42 I have good news and bad news I just upgraded my entire TC from Duet 2 to Duet 3 hardware and also to 3.5b1.
The good news is that this issue did not happen anymore at all with the duet 2 hardware (on 3.4.5), however, now with Duet 3 on 3.5b1, it happens again I haven't tested Duet 3 on 3.4.5, so not sure if it's Duet 3 specific or 3.5b1...

Any ideas what could have caused this regression?

dc42

@Diamondback please check whether the symptom is exactly the same as you describes at the start of this thread, and start a new thread with any appropriate amendments. Post the config.g and relevant homing files for your new configuration.

Diamondback

@dc42 Hm, this is very odd timing.... It turns out, the grub screw of my coupler was loose and that's what made it look like it wasn't homing correctly... Weird that this happens right after a firmware upgrade

Not 100% sure this was the only issue, but I will assume so for now, sorry for the confusion.

dc42

@Diamondback thanks for the update! Over the years I have seen many instances of faults being blamed on a software update, when in reality something else just happened to go wrong at the same time.

Diamondback

@dc42 Yea same... I hate bad timing...