@Thalios said in Problem with Laser filament monitor:

Doesn't work, even with that indirect thing.

Reading I get:

Duet3D laser filament monitor v2 with switch on pin io3.in, disabled, allow 200% to 3000%, check every 3.0mm, version 2, quality 223, brightness 255, shutter 91, measured min -2% avg 152% max 273% over 466.5mm

I will try with a different rod (I have stainless steel coming which i'll sand to make non shiny)

But so far, i'm lost...

This is what I was getting with the indirect monitor using MK3 hob and a rigid mount right above my direct drive extruder:

9/12/2020, 9:03:10 PM M591 D0 Duet3D laser filament monitor v2 with switch on pin e0stop, enabled, allow 200% to 260%, check every 3.0mm, version 2, quality 221, brightness 255, shutter 84, measured min 225% avg 240% max 257% over 13515.3mm

@T3P3Tony

Thanks Tony the links were very helpful. I agree fixing the hot end clearance issue on the first layer is a better solution. My problem is that when I am doing a print that takes up a large part of the surface area on the bed 90% of the bed will be at the right clearance but the 10% is not due to the bed not being perfectly flat. So, correcting the problem sounds easier than it might be. Which means if I want to use the sensor I have to stay and monitor the entire first layer to restart the print if it pauses at these spots. After the first layer is down the problem no longer exists and the sensor will only pause the print when it should.

Based on your comments on calibration should I be able to set R minimum to a negative value? It seems not, because when I do that the M591 command ignores the R value and substitutes 0-160 for the R values. Is that what it should do?

These are the typical numbers I am getting. Once I get past any first layer issues this is a typical D591 result. It seems really good to me, would that be correct?

m591 d0
Duet3D laser filament monitor v2 on pin e0stop, enabled, allow 0% to 250%, check every 5.0mm, version 2, quality 222, brightness 255, shutter 77, measured min 155% avg 165% max 176% over 80.9mm

Thanks again for any help here.

Wow! Now either you are amazing fast or your were already thinking about making the very same change.

That's great. Looking forward to the update.

Thanks - making more sense now. So I am at about hour 15 of a long print and had a failure. I'm not too sure when 😞 I resumed the print and will see what happens ......

In any case - the M591 D0 now reports

Pulse-type filament monitor on pin e0stop, enabled, sensitivity 7.000mm/pulse, allowed movement 75% to 125%, check every 15.0mm, measured sensitivity 7.854mm/pulse, measured minimum 80%, maximum 93% over 369.1mm

Nothing has been changed except this print does have a fair number of retracts. Several questions:

Does the measured sensitivity going down suggest slippage in the sensor (it's two wheels one of which "encoded" with holes) ?

Looks maybe like the minimum % threshold may have been triggered -- hard to tell as I took the above measurement after the restart (was not thinking)?

Beyond checking the mechanical aspects of the sensor - would setting to E21 (i.e. say 3 x nominal sensitivity) tend to make sense for tuning or does that seem a bit course ?

@chickenwoman is it possible to confirm this using this method:

access the back of the filament monitor so you can mark a line on the hob/case as a reference. (say vertically). then you can try moving the filament a known distance back and forwards through the monitor to see if you can generate slips

So it turns out that I am not to be trusted ..... I got "switched around" with the E0/E1 connectors and LED's.

All good now ... sorry for the false alarm.

I have ordered the rotating mag filament monitor but I would still like to see if this laser monitor can be salvaged. I would also really like to see if a small micro switch could be added for the static filament present state.

I am not great at CAD but this would be the difference.

Get rid of the spring and idler pulley Use a geared MK3 style dual extruder A support at the top and bottom to keep the filament straight and reduce slips due to the filament curve Add a micro switch inline (normally open)

Screenshot 2020-08-22 at 8.01.11 PM.png

Screenshot 2020-08-22 at 8.00.28 PM.png

The top gear would use a linear bearing and a stationary 3mm axle based on this assembly:
https://amzn.to/3hpxzbs

I could provide the stp file if anyone knows how one might create the enclosure around this concept?

Really appreciate the thoughtful, detailed response, thank you! I've not had many issues with my various Duet products, but when I do this forum has always been incredibly helpful.

I will check the cable crimps for sure, great idea (I created the cable from the Duet wiring kit). The cable is not shielded, and it is zip-tied into the wire bundle, so your point about noise from the extruder motor cable is very plausible; I will separate it from the bundle on the next run and see if that eliminates the false alarms. Perhaps I should even try a shielded, pre-made cable to eliminate both possibilities.

Sounds like my setup is similar to yours...I created a custom mount to place the MFM just before the BMG extruder....eyeballing it it's probably ~50mm or less.

I do have a long bowden tube to get outside of a normally enclosed case, but it is almost entirely pre-extruder. Collet clips are in-place, and I did carefully cut (and re-cut, sigh) the short tubes between the MFM and extruder, and extruder to hot-end, so there is no obvious flex when the extruder is pushing. Here is my setup:

HotEnd.jpg

Thanks again for all the great tips, I will check all of these as well as increase the measurement distance a little further, and see if I can eliminate the false alarms.

@cherringshaw Please start a new thread.

@dm86 that agc value is high. please mail me, info@duet3d.com and we will work out how to proceed because we don't yet have the new housings needed for a direct replacement.

I have been searching around the forum tonight leading me to several "indirect filament sensor" threads. I believe the answer to my question above is yes. The sensor detects movement and not presence.

The laser filament sensor does have an input for a micro switch but most of the mods do not use it. I must just have an unusual use case in wanting to take advantage of the static state of knowing if filament is loaded. I was using this information to automate startup and printing.

Hi please contact info@duet3d.com to inquire about available options. Please include your order information and a link to this thread.

@Nathan said in Magnetic Rotating Filament Sensor not working:

Error: M591: Remote ports not yet supported by this command

Found the problem:

https://duet3d.dozuki.com/Wiki/Duet_3_firmware_configuration_limitations

Filament monitors for extruders driven by expansion boards and tool boards are not yet supported. Support is planned in release 3.3.0. The filament monitor will need to be connected to the board driving the corresponding extruder.

@shinook said in I think my new Magnetic Filament Monitor is dead.:

I'm open for suggestions.

I think we were going to try replacing it if you're still interested in doing that. I'm not sure what the current stock situation is, but check with filastruder if they can replace and if not fill out the form here to see if you can get something directly from Duet. https://www.duet3d.com/warranty

In either case, refer to this thread.

In that case, see the form here: https://www.duet3d.com/warranty

@Phaedrux Thank you, I appreciate it.

ah, yeah, it seemed the manufacturer only have two distributors for their sensor and not using digikey/mouser/etc, not sure if its easy get a hold of a one-off. if you go with the plan to scavenge parts of another board pay attention to the solder temp and times listed for the sensor.

as for the passive components, unless there is a note on the schematic just pick the cheapest with the correct resistance and footprint. if there are special conciderations like tolerance, power rating or temperature coefficients its usually noted somewhere. like you see the inductor specifies 100Mhz.

Part Number
PAK9125LP-xxxx

Where to Buy
North America:

WPG America (Distributor)

Website: http://www.wpgamericas.com/contact-us/

Taiwan and China:

AIT Group (Distributor)

Website: http://www.wpgholdings.com/aitg/pline_detail/en/PixArt

I do have a Duet laser sensor and was thinking of maybe doing one of these two mods

https://forum.duet3d.com/topic/10042/indirect-bearing-laser-filament-monitor-concept

https://forum.duet3d.com/topic/15799/laser-filamant-sensor-with-switch-housing