Core XY movement issues

[JoergS5]

@deckingman

Ok, I will try to understand and compare the different firmware versions and verify whether there are errors in it. My guess is, that processing M92-M350 produces different rounding errors than M350-M92.

You said that a lot of people are using the code and an error would be detected. But if the rounding error is small enough for most settings, nobody will mention, but push it to mechanical deficiencies.

[dc42]

@joergs5 said in Core XY movement issues:

@deckingman

Ok, I will try to understand and compare the different firmware versions and verify whether there are errors in it. My guess is, that processing M92-M350 produces different rounding errors than M350-M92.

You said that a lot of people are using the code and an error would be detected. But if the rounding error is small enough for most settings, nobody will mention, but push it to mechanical deficiencies.

Any rounding errors would be far too small to have this much effect, and when using the same microstepping and steps/mm on the X and Y motors, they would affect both motors equally anyway.

Can you confirm that if you swap the order of the M350 and M92 commands back to your original order, and adjust the M92 values as needed, the problem returns?

[FxxToo]

@dc42
Yes I can. I posted that result here : https://forum.duet3d.com/post/55484
I had found a post that you had done about putting the M92 Xxx Yxx, with the steps set for 1/16 step rate before the M350 command. I changed that and my issue with the Y moving with the X and vice versa, Stopped. I was asked if I could replicate it. I tried and I could. I thought maybe I had something else that could effect it in my config file, so I posted it after I had changed it, leaving the original statements marked in it, obviously commented out.

Firmware Name: RepRapFirmware for Duet 2 WiFi/Ethernet
Firmware Electronics: Duet Ethernet 1.02 or later
Firmware Version: 1.21 (2018-03-21)
Web Interface Version: 1.21Firmware Name: RepRapFirmware for Duet 2 WiFi/Ethernet
Firmware Electronics: Duet Ethernet 1.02 or later
Firmware Version: 1.21 (2018-03-21)
Web Interface Version: 1.21
RJ

[JoergS5]

@dc42 how about enable logging M929 (or more) and printing a simple line, this should give information whether the second stepper moves unexpectedly.

According to:
https://duet3d.dozuki.com/Wiki/Logging

I believe you that the rounding errors are not applicable, but it's maybe another reason in the code.

[JoergS5]

@fxxtoo said in Core XY movement issues:

; Endstops
M574 Z1 S0 ; Set active low endstops
M574 X1 Y1 Z2 S0

I think it has nothing to do with the thread problem, but I am confused by a config setting: why are there two Z endstops, one for Z1 and one for Z2, low end and high end?
(If the second is a Z-probe, I thought you need to set it as S2 instead of as Z2)

[FxxToo]

@joergs5

I was going to try it with the end stop on either end the of the Z. So I had done that before my issue was discovered. I haven't gotten to those tweaks or others, like the accelerations, jerk factor and lots of others. Still learning about a lot of this. I do appreciate the input.
RJ

[dc42]

@fxxtoo said in Core XY movement issues:

@dc42
Yes I can. I posted that result here : https://forum.duet3d.com/post/55484
I had found a post that you had done about putting the M92 Xxx Yxx, with the steps set for 1/16 step rate before the M350 command. I changed that and my issue with the Y moving with the X and vice versa, Stopped. I was asked if I could replicate it. I tried and I could. I thought maybe I had something else that could effect it in my config file, so I posted it after I had changed it, leaving the original statements marked in it, obviously commented out.

Firmware Name: RepRapFirmware for Duet 2 WiFi/Ethernet
Firmware Electronics: Duet Ethernet 1.02 or later
Firmware Version: 1.21 (2018-03-21)
Web Interface Version: 1.21Firmware Name: RepRapFirmware for Duet 2 WiFi/Ethernet
Firmware Electronics: Duet Ethernet 1.02 or later
Firmware Version: 1.21 (2018-03-21)
Web Interface Version: 1.21
RJ

Thanks. I'd like to get to the bottom of this, so please can you:

1. Using your existing config.g, send M92 and check it reports the correct steps/mm. X and Y should be reported as 320 because the M350 command will have adjusted them.

2. Also send M667 and verify that the axis factors reported are all 1.0.

3. Change config.g to the version that gives problems. Verify that the problem still exists. Then run M92 and M667 again and check what steps/mm and axis factors are reported.

4. After that, try deleting and re-typing the M92 X320... line in case it contains any non-printing characters, and see if the problem is still present.

Thanks - David

[FxxToo]

@dc42 @ everyone
Thank You Dave!!! You made me find the problem. By going in fresh this am and starting to do the test, I discovered that in my original config.g file posted here, the original M92 statement was incorrect, it read "M92 Y320 Y320 Z1400 E420 ". I guess my mind corrected it every time I looked at it. Your #4 test was what made me catch it. So I have corrected it and all seems to be correct. I ran the test with the bad M92 statement and got this
9:43:05 AM
M92
Steps/mm: X: 349.956, Y: 320.000, Z: 1400.000, E: 420.000:420.000:420.000:420.000:420.000:420.000:420.000:420.000:420.000

I can't really comment on the inner workings, but it shows me that the two motors were not in sync. So my problem is solved and the mystery of why is now as well.
I apologize for all of the time and effort that was put in to finding my stupid mistake and thank everyone for their time and effort.

[dc42]

I'm glad we got to the bottom of it. The default XY steps/mm is 87.4890 (a hangover from the first printer to use a Duet), which explains how you got the 349.965 steps/mm after changing the microstepping.

[JoergS5]

@fxxtoo What the heck, I checked your config files multiple times to find something and overlooked it also.
Glad that you found the solution now!

[FxxToo]

@dc42 Amen to that!!!!

[FxxToo]

@joergs5
Yes.. I can't begin to tell you how many times that I looked at it and missed it.. And I wear glasses!

[deckingman]

@fxxtoo said in Core XY movement issues:

@joergs5
Yes.. I can't begin to tell you how many times that I looked at it and missed it.. And I wear glasses!

If it's any consolation, I too didn't spot it (and I wear glasses too).
But I'm glad you got it sorted because I was starting to doubt my own sanity.

[FxxToo]

@deckingman Thanks, sometimes to close to the forest to see the trees!

[deckingman]

@fxxtoo We should have gone to spec savers maybe

[T3P3Tony]

@fxxtoo
Thanks for sticking with it while we have been throwing ideas at you, as @JoergS5 says.. you now know how it all works very well!

[FxxToo]

@t3p3tony
Thanks for the kind words, but I have just started the learning curve.