Rotating Magnetic Sensor - Keeps Pausing Printer

T3P3Tony

@petrkroupa please share the gcode file you were printing that has this issue. Also what Z height did you have the really bad low value.

PetrKroupa

@t3p3tony - Here is file - 0.6 nozzle, PLA https://uloz.to/tamhle/FnGywCyC0Lbx#!ZGNmZQR2AwZ1ZmV0BGV3LzExATWvBUuvGQOzJUqHASq3MwSvBD==
It is 8Mb. I had to upload it to another server. Anyway, the error occurred many times in the first 4 layers. Then I turned off the sensor (m591 D0 S0). Today morning before the end of printing I tried M591 D0 and measured sensitivity was min -53% max 105%. Printing was completed successfully without any problems.

Z height? Do you mean : G31 P500 X26 Y0 Z1? Or?

T3P3Tony

@petrkroupa thanks. The answer to the Z height question is that it happened many times in the first few layers. Just makes it easier to reproduce if I don't need to print the whole part.

PetrKroupa

@t3p3tony - maxi_dvojka_CUT- Telo32-2_0.6n_0.3mm_PLA_velkej_2h10m.gcode

OK, here is a cut off model. It is only 1.5 mm high. Sliced with same setings.

I thing my Z height is OK. Not too much on the bed. BuildTak doesn't like it. Rather, I feel like I'm almost too high. However, the value entered in G31 still depends on the position of the probe. I use BLTouch and I believe it's ok. Anyway, I believe this is not a filament sensor problem.

first layer:

alankilian

@petrkroupa I notice your layer change has something I've never seen before:

Two very fast negative movement on the extruder.
Normal speed negative movement on the extruder
Normal speed positive movement on the extruder

This is the only unusual thing I see.

Starting at line 730 in the file:

;WIPE_START
G1 F14400
G1 X264.546 Y233.289 E-.42543
G1 X264.445 Y232.993 E-.04957
;WIPE_END
G1 E-.025 F2400
G1 Z.7 F18000
G1 X265.067 Y236.944
G1 Z.2
G1 E.5 F2400
;TYPE:External perimeter

PetrKroupa

@alankilian - Hmm Im using prusa slicer. the question is what is there for. Most likely it's a remnant of the original profile. But the error always occurs somewhere during the layer, I never observed it at the beginning. But good point, thanks. I try remove it.

alankilian

@petrkroupa If you can slice something smaller, I can try printing on my Delta and see if I get errors also. (If you can center at (0,0) that would be even better.)

dc42

@petrkroupa likewise, if you can slice it centred at (0,0) I will try it on my delta and on my toolchanger.

PetrKroupa

@alankilian, @dc42 - Today i will finish last big print. Then I will try to create some small GCODE (50 * 100mm) where the error will definitely show up. I'll test it and upload it here. We'll see what shows. So far, it seems that the error does not occur during the first layer.

PetrKroupa

@dc42 - One question, if the problem was somewhere on the HW side, the measured % value would be lower. Because the sensor simply turns less than the extruder. Correct?

However, this does not explain how a min -53% can happen. The extruder would have to create the filament.

Am I thinking right or am I completely out of it?

PetrKroupa

I finally figured out what was happening.

sensor.mp4

When the filament is slightly bent, the sensor restarts. Not always. But I managed to film it during manual extrusion. What is certain is that it cannot be wiring because nothing moves. It's weird that it only showed up with BETA6, but until then I didn't have a problem with it.

The question is why the sensor restarts.

alankilian

@petrkroupa said in Rotating Magnetic Sensor - Keeps Pausing Printer:

When the filament is slightly bent, the sensor restarts

OH! That's a good catch.

dc42

@petrkroupa is the AGC value reported by M591 consistently below 100 ?

PetrKroupa

@dc42 - Yes, it is solid somewhere between 91-93. I also verified that the spindle rotates freely and has no axial move.

I tried to tap the sensor in various ways, bend the connectors and twist it in every way. Strange....

dc42

@petrkroupa I think either there is a dodgy power connection somewhere, most likely in the wiring but possibly on the PCB itself; or something is causing the watchdog timer to time out. I can't see any reason in the firmware why the watchdog timer would time out, other than bad power or a transient causing the microcontroller to get into a bad state.

If you are sure that you can't provoke it or temporarily fix it by bending the wiring, then I suggest we replace the circuit board. Please email warranty@duet3d.com with a link to this thread.

PetrKroupa

@dc42 - I will make new wiring to sensor. I have order new sensor to my second printer. After it arrives, I will try found where is problem. If you are sure there is no FW reason to restart sensor intself, it must be somewhere in board/wiring. And since only the sensor is restarted and not tool board, the solution must be easy.

Waranty for that small and cheap thing it doesn't make sense to me. Thank you anyway.

I think we can close this thread. Thank you for your help.

T3P3Tony

@petrkroupa thanks for the diagnostic work. I came here to say i could not reproduce the problem with my test setup and your earlier print code - should have checked here again first!

Please do update this thread once you have tested your new board for the other printer.

CNCModeller

Hi All,
I'm still getting behaviour that I don't understand, I'm using the automated meta gcode for generating a PA calibration print. I've attached the gcode and some log files. The log file contains a readout of the filament sensor status triggered at each layer change.

Inspecting the print optimal PA seems to be at about 25mm, Pressure advance: 0.25

eventlog.txt

PATuning.g

The sensor is tripping out at about 40mm, but the measured sensitivity seems to start gradually reducing at about 20mm (0.2 PA).

Not sure if this data is useful, seems to me that the brim prints OK at slower speeds with measured calibration there being in line with settings. So IMO that seems correct.

The speeds don't vary after the first layer so the only thing that's changing is the PA as we go up the tower. And the first 20mm of Z seems OK in terms of measured filament usage. But starts to decrease after that. But then warns of too much filament?

As I said it doesn't make sense to me.

Hope this helps the bigger picture.

Cheers
Barry M

T3P3Tony

@cncmodeller you have your filament monitor configured as a pulse type not a magnetic type. If it is pulse type the the configured sensitivity looks wrong.

CNCModeller

@t3p3tony said in Rotating Magnetic Sensor - Keeps Pausing Printer:

@cncmodeller you have your filament monitor configured as a pulse type not a magnetic type. If it is pulse type the the configured sensitivity looks wrong.

Hi Tony.
It's a custom pulse sensor based on one of the output channels of a 600ppr (2400cpr) encoder and an old extruder gear system.

The measured values are consistent with the settings. It works well most of the time, but appears to glitch out every now and then.

Wasn't sure of this was an appropriate place to post but it seems relevant to this thread as the only thing changing is PA.

Hope that clarifies things.

Best regards
Barry M