Jam detection help please

Is there a step-by-step guide to configuring jam detection on Repetier, or does anyone have any suggestions to help, please?

I am using Repetier Host v2.0.0, Server v0.80.3 and firmware v0.92.9 and have added a Hall effect filament jam detector that pulses onto pin D40. 

I have configured it in firmware using:

  • Extruder stepper:           255 steps/mm
  • Jam_Steps:                   1366 steps (the detector gives 1 step every 5.357mm so I multiplied the steps/mm of the extruder by 5.357)
  • Jam_Slowdown_Steps: 1500
  • Jam_Slowdown_To:       70%
  • Jam_Error_Steps:          2000
  • Jam_Min_Steps:            50

When I test the extruder by extruding 100mm it does this fine but the jam detector reports that it is slipping and eventually reports a jam when I try to print

Am I doing something obviously wrong? Is there any way to display the pulses or steps that the jam detector is reporting?

And as a secondary point, is there an optimum length per pulse for the detector? I am able to add more magnets to increase the pulses per turn so can easily amend the current setting.

Thanks.

Richard

Comments

  • I think I've answered some of my questions. I found the M602 command and have been using that to debug and to see the pulses and am now tuning it to work effectively.

    I'd still like to know if there is an optimum pulse / mm or pulse / extruder steps setting or design parameter so that I can optimise that.

    Richard




  • Optimum would be a Jam_Slowdown_Steps bigger than anything you experience in normal working situations. WIth debug you can already see what it really measures then add sone 30% on it as a start. Error should be again 30-50% on top I'd say. If you have a real error you will trigger any value anyway but on the other side you also want to trigger early.
  • Repetier said:
    Optimum would be a Jam_Slowdown_Steps bigger than anything you experience in normal working situations. WIth debug you can already see what it really measures then add sone 30% on it as a start. Error should be again 30-50% on top I'd say. If you have a real error you will trigger any value anyway but on the other side you also want to trigger early.
    Thank you for your response, Repetier!

    To check my understanding, please. If the highest steps / pulse I see in normal use is, say, 1000 then I should set Jam_Slowdown_Steps to 1,300 and Jam_Error_Steps to approx 1,700 - 2,000

    Am I understanding correctly?

    Thanks.

    Richard
  • Oh, and one further question - is it possible to edit the Jam settings anywhere other than by recompiling the firmware and uploading it? Is it available in the EEPROM or elsewhere accessible from the Repetier Server or Host?

    I've looked in both but not been able to find it yet.

    Thanks.

    Richard
  • It is fixed in firmware, no eeprom. But you can change it by gcode:

    - M604 X<slowdownSteps> Y<errorSteps> Z<slowdownTo> T<extruderId> - Set jam detection values on a per extruder basis. If not set it uses defaults from Configuration.h

    And yes, you understood me correctly regarding steps.
  • Thanks again - much appreciated! I'll be able to play with the values and then lock them in to the firmware when I've goyt them sorted.  

    Richard
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