Weird magnetic filament sensor values

hbar

I am getting weird values and not enough movement alerts from the magnetic filament sensor lately. I had been using it with some success until today. I was wondering if anyone had any ideas. I am running Duet 2 wifi with firmware version 3.1.1.

M591 D0
Duet3D rotating magnet filament monitor v3 on pin e0stop, disabled, sensitivity 24.55mm/rev, allow 20% to 140%, check every 45.0mm, version 3, mag 130 agc 120, measured sensitivity 15521.55mm/rev, min -33% max 476% over 1546.1mm

Thanks in advance

alankilian

It might be a good idea to open it up and see if the magnet shaft is still able to rotate with low friction or if it's jammed somehow.

hbar

When I opened it up there was some ground up filament in the sensor. I haven't done any long running prints but this looks to have been the problem. Thanks!

alankilian

YEAH!

That's great to hear.

dc42

@hbar said in Weird magnetic filament sensor values:

I am getting weird values and not enough movement alerts from the magnetic filament sensor lately. I had been using it with some success until today. I was wondering if anyone had any ideas. I am running Duet 2 wifi with firmware version 3.1.1.
M591 D0
Duet3D rotating magnet filament monitor v3 on pin e0stop, disabled, sensitivity 24.55mm/rev, allow 20% to 140%, check every 45.0mm, version 3, mag 130 agc 120, measured sensitivity 15521.55mm/rev, min -33% max 476% over 1546.1mm
Thanks in advance

The "agc 120" value is very close to the upper limit, and suggests that either the washer magnet has weakened or it is not close enough to the sensor chip. The agc should normally be below 100.

A Former User

@alankilian I am experiencing the same issue with theese values:

M591 D0
Duet3D rotating magnet filament monitor v3 on pin e0stop, enabled, sensitivity 24.75mm/rev, allow 65% to 130%, check every 3.0mm, version 3, mag 130 agc 98, measured sensitivity 24.83mm/rev, min 96% max 104% over 709.1mm

I'm a little afraid to open the sensor...isn't it "dangerous" to open the case? Aren't there little screws of little springs who could jump out? Isn't there the chance to compromize some alingment? Thanks!

droftarts

@the_dragonlord @alankilian
See the troubleshooting section here: https://duet3d.dozuki.com/Wiki/Duet3dFilamentMonitor_RotatingMagnetVersion#Section_Errors_during_operation

Aren't there little screws of little springs who could jump out?

See https://duet3d.dozuki.com/Wiki/Duet3dFilamentMonitor_RotatingMagnetVersion#Section_Assembly
There's a spring, but it's not that small. And you're actually trying to improve alignment!

Ian

A Former User

@droftarts said in Weird magnetic filament sensor values:

@the_dragonlord @alankilian
See the troubleshooting section here: https://duet3d.dozuki.com/Wiki/Duet3dFilamentMonitor_RotatingMagnetVersion#Section_Errors_during_operation

Aren't there little screws of little springs who could jump out?

See https://duet3d.dozuki.com/Wiki/Duet3dFilamentMonitor_RotatingMagnetVersion#Section_Assembly
There's a spring, but it's not that small. And you're actually trying to improve alignment!

Ian

ok, thanks

BoA

I will join this, as I bought second magnet filament monitor, and it barely works. Also I have:

Duet3D rotating magnet filament monitor v3 on pin io7.in, enabled, sensitivity 25.40mm/rev, allow 50% to 150%, check every 12.7mm, version 3, mag 126 agc 128, no calibration data

agc 128 I belive is the limit of this value. I tried to sand down an enclosure a little, but no luck.

alankilian

You can test by putting something nonconducting on the PCB and setting the magnet on top of the sensor IC to see if you can get the AGC down by putting the magnet closer.

Then, put some clay or something on the IC and assemble the unit.
Disassemble the unit and measure the thickness of the clay to see how far away from the sensor your magnet is when assembled.

Sand to adjust the clearance to match the thickness of the whatever-you-used in the first step.

hbar

@dc42 Thanks for pointing that bit out. I had missed that on the docs site. I filed it down some and it seems to be at a more acceptable range.