Problem with calibrating magnetic filement sensor

Frankzz

@Phaedrux
Yes, I did the wiring yesterday, did some testing and started a 60 hour print.
It worked for about an hour then it started saying "too little movement"
I have set the tolerance to 10%-125%, just as stated before.

But there are no problems, no clog and filament extrudes fine when doing it manually at highest speed.
I tried to make it work for 2 hours. In the end I got sensitivity value in the 1000 and it would not work at all.
I tried it this morning with the same result.

So I actually think there is something wrong with the sensor.
So yes, I would like a replacement sensor.
Frank

dc42

[EDITED] I suspect that the reason for the small sensitivity changes is that the average print speed is changing and your extruder suffers from nonlinear extrusion, i.e. the steps/mm goes up a little as the extrusion rate increases.

When the sensitivity gets very high (you mentioned 1000), does the AGC still read in the 80 to 90 region?

Frankzz

@dc42
AGC is 76-78. Now the sensor is not working at all.
I can´t post the respons from printer since I am at work. Will do that later today.

The problem just escalated until it stopped completely.
When printer pauses I can extrude manually with highest speed. Then I resume and it just went shorter and shorter distance until it paused again.
I the end it pause direct but I see it extruding.

So right now I like to try a new sensor.

Frank

Frankzz

Here is the last numbers when the sensor still kind of worked
00:49:42M591 D0
Duet3D magnetic filament monitor with switch on input 2, enabled, sensitivity 25.58mm/rev, allow 10% to 125%, check every 5.0mm, version 3, mag 131 agc 76, measured sensitivity 29.46mm/rev, min 26% max 112% over 407.0mm
00:49:28M591 D0
Duet3D magnetic filament monitor with switch on input 2, enabled, sensitivity 25.58mm/rev, allow 10% to 125%, check every 5.0mm, version 3, mag 131 agc 76, measured sensitivity 28.48mm/rev, min 60% max 108% over 307.8mm
00:48:54M591 D0
Duet3D magnetic filament monitor with switch on input 2, enabled, sensitivity 25.58mm/rev, allow 10% to 125%, check every 5.0mm, version 3, mag 131 agc 76, measured sensitivity 27.06mm/rev, min 97% max 102% over 102.0mm
00:48:47M591 D0
Duet3D magnetic filament monitor with switch on input 2, enabled, sensitivity 25.58mm/rev, allow 10% to 125%, check every 5.0mm, version 3, mag 131 agc 76, measured sensitivity 27.00mm/rev, min 97% max 102% over 61.4mm

Frankzz

Here is the read out last night when it just gave up
00:58:28M591 D0
Printing paused at X744.9 Y222.7 Z6.0
Duet3D magnetic filament monitor with switch on input 2, enabled, sensitivity 25.58mm/rev, allow 10% to 125%, check every 5.0mm, version 3, mag 130 agc 76, measured sensitivity 17063.90mm/rev, min 100% max 100% over 16.7mm

I just tried again. First it just stopped more or less direct.
18:01:03M591 D0
Printing paused at X424.3 Y225.9 Z6.0
Duet3D magnetic filament monitor with switch on input 2, enabled, sensitivity 25.58mm/rev, allow 10% to 125%, check every 5.0mm, version 3, mag 129 agc 76, measured sensitivity infmm/rev, min 0% max 0% over 14.4mm

Guessing it is not spinning so I pulled the filament and tested so the sensor rotor moved. It did.

Resumed again and got this far
18:04:43M591 D0
Printing paused at X135.5 Y298.0 Z6.0
Duet3D magnetic filament monitor with switch on input 2, enabled, sensitivity 25.58mm/rev, allow 10% to 125%, check every 5.0mm, version 3, mag 132 agc 78, measured sensitivity 28.65mm/rev, min 1% max 110% over 108.8mm.

Can you please give advise what to do?

Frank

dc42

Hi Frank, I authorise a replacement sensor for you under warranty. Please contact your supplier and refer them to this forum post for authorization.

Frankzz

@dc42
Ok will do.
I just stopped the print, deleted the M591 line in config and will try to resurrect the print with out sensor
If that works it is definently the sensor

Frankzz

Now it is printing fine. It will not tell me if it stops extruding but I can find the height and use resurrect.

But just when the print started I got this message on webinterface

Connection Lost
The connection between the browser and your machine has been interrupted.

Reason: Unknown (SyntaxError: Unexpected token , in JSON at position 845)

Please reload the web interface to proceed.

Tried to reload, restart computer and restart router. Nothing helped.
Don´t want to restart printer in mid print.
Is this a known issue?

BoA

Got similar problem. AGC - 122. I ended up sanding resin case and the magnet sensing IC. Now agc is 56 and all problems solved.

Frankzz

@BoA
I started out with AGC 114. (See previous posts)
AGC now is around 80 and that is well within specs.

It did work fine for a while and that tells me the issue is the sensor.
But If the next sensor does the same I will try to this one more to see if it helps.
Does anyone know the lower tolerence of AGC ?

Frank

Phaedrux

@Frankzz said in Problem with calibrating magnetic filement sensor:

Connection Lost
The connection between the browser and your machine has been interrupted.
Reason: Unknown (SyntaxError: Unexpected token , in JSON at position 845)
Please reload the web interface to proceed.

What version of firmware and DWC are you running? There may be a version mismatch.

Currently supported versions are FW 2.05.1 and DWC 2.0.7 and FW 3.1.1 and DWC 3.1.1

Frankzz

@Phaedrux
The web interface has worked fine for 8 weeks when I upgraded the printer to Duet.
This happened right when I resumed a print. Have a hard time believing it has something to do with versions.

I switched off and on the wifi module in Duet and for some reason it had change the address.
Used the address the came up in the display and now it works again.

cherringshaw

Good morning Duet collective,

I too am having some calibration issues for the rotating magnetic sensor. My setup: New-ish Railcore printer, BMG extruder, v1.7a magnetic sensor board mounted just before it, black FDM self-printed case sanded down to achieve AGC of ~80-81. There is an approx 1m wire from the sensor back to a Duet Wifi v1.02 board, running firmware 2.05.1 per a previous recommendation.

My issue is inconsistent triggering of the stop actions.

I started with this somewhat generic but tuned config:

M591 D0
Duet3D magnetic filament monitor on input 3, enabled, sensitivity 25.20mm/rev, allow 70% to 130%, check every 3.0mm, version 3, mag 130 agc 81, measured sensitivity 25.10mm/rev, min 96% max 105% over 446.9mm

In this configuration I get no more than 20-30 minutes of runtime before it bombs out with "Too little extrusion", "Too much extrusion", or "Sensor not reporting"...? When extruder gears are turning, the status light is almost solid green. I've tried a variety of PLA filaments from light to dark, same deal. I hit "Resume" and the print keeps going.

The print itself comes almost nearly flawless, like most things printed on the Railcore. I've tested with and without the sensor enabled on small items....they look identical coming off the plate, so I do not think the filament is under/overflowing at any time during the print, at least to my eye.

Based on some ideas in this thread (thank you), I changed slightly to this configuration:

M591 D0
Duet3D magnetic filament monitor on input 3, enabled, sensitivity 25.10mm/rev, allow 50% to 150%, check every 5.0mm, version 3, mag 130 agc 80, measured sensitivity 25.10mm/rev, min 91% max 107% over 22108.7mm

This went better, and on a 32 hour (scheduled) print it only stopped three times...but one was overnight so I lost several hours in standby until I could hit "Resume", which is a bummer.

Last night I hit "M591 D0 P0" during a long print to disable the sensor overnight, then re-enabled it in the morning and it ran fine (one more stop) before finishing a few minutes ago....but disabling it kinda defeats the purpose.

Just curious if you think this is more of a configuration / tuning issue, or is there something maybe with the wiring (too long?) that could cause an intermittent bad signal? Is the error calculation somehow cumulative, so eventually the small errors build up into a larger one that hits the threshold?

Overall happy with the unit and it seems like it's doing it's job very well....I just need to dial it in to avoid these false alarms on long, overnight prints.

Thanks!
Chris

Phaedrux

@cherringshaw Please start a new thread.