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Run Out Fail, but sensor OK?  

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Doak
 Doak
(@doak)
New Member
Run Out Fail, but sensor OK?

I just had a 20hr print run out of filament in the home stretch.

Running 3.8.1-2869 on a Mk3S

IR Sensor appears to flip from 0 (no filament) to 1 (with filament) very nicely and the mechanism is moving well with no real resistance.

The filament sensor was enabled.

Autoload was NOT enabled, though I have now flipped it back on.  Thinking back, I’m not sure autoload has ever actually worked since I did the 'S’ upgrade.  I think I just forgot that was still a thing…

Hoping you can point me in the right direction as I haven’t seen a KB that really looked like what I’m seeing.  Or I have failed at my google-fu.

So, if I’ve got the IR sensor value updating properly, what can I have wrong that would break the sensor despite reading the value?  It's kind of like there's a disconnect between the printer getting the sensor input and it then doing anything with that information.

Posted : 28/02/2020 11:14 pm
Nikolai
(@nikolai)
Noble Member
RE: Run Out Fail, but sensor OK?

I would suggest to try to reproduce this case with the same(similar) filament.

If electronically everything is fine, then it must be mechanical issue. Like stuck lever or loose connector.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Posted : 28/02/2020 11:36 pm
Doak
 Doak
(@doak)
New Member
Topic starter answered:
RE: Run Out Fail, but sensor OK?

@nikolai-r

After the print, the sensor value was zero.  I stuck some spare filament into the extruder and I can feel the ball bearing move and the sensor registers one.  I can slide filament in and out as slow or fast as I want and the sensor always immediately registers the appropriate one or zero.

Assuming 0 = empty and 1 = full.  If that's backwards, then I've found my problem.

It really is like it KNOWS the filament is present or absent, but it just doesn't care.  Which is weird...  It'd be easier if the sensor wasn't registering at all or was stuck.

 

This post was modified 4 years ago by Doak
Posted : 28/02/2020 11:47 pm
vintagepc
(@vintagepc)
Member
RE: Run Out Fail, but sensor OK?

I'd highly suggest the mod that solders an LED to the sensor if you are comfortable doing it. Many problems are from flickering sensor readings as the filament moves, and "static" tests from inserting/removing a short piece don't show anything. The LCD is also somewhat slow to update and so misses faster flickers that are easily visible with the LED mod.

Think about it- if your sensor is right at the edge for some 1.73 mm filament (thereby working most of the time), what happens if a section that is narrower than that comes along?

Posted : 29/02/2020 12:27 pm
j.gabbai liked
j.gabbai
(@j-gabbai)
Estimable Member
RE: Run Out Fail, but sensor OK?

The sensor either if there is a filament or not, but does not know if it advances ... It may be your problem

Clogged nozzle, filament stuck for various reasons

L'impression 3D est l'avenir plus ou moins proche de toute l'industrie. Sa découverte ouvre l'esprit à la création, mais aussi à de nouveaux métiers et pour le moment un atout peu ordinaire à mettre impérativement sur un CV.

Posted : 29/02/2020 2:49 pm
Doak
 Doak
(@doak)
New Member
Topic starter answered:
RE: Run Out Fail, but sensor OK?

@vintagepc

If I'm getting you:  There are issues with sensor performance when you are riding the line between "Too Much" and "Too Little" causing it to flip between 0/1?  Or are you saying the light itself has an issue with flickering?

This brings back nightmares of thermal alerts from server rooms that'd just ride the alert threshold, paging me over and over and....

Posted : 29/02/2020 3:36 pm
vintagepc
(@vintagepc)
Member
RE: Run Out Fail, but sensor OK?

Just saying that if you do that mod it is far more reliable as an indicator of a marginal sensor adjustment position than the LCD itself

Posted : 29/02/2020 4:33 pm
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