Adding skip detection during firmware self-test
 
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Adding skip detection during firmware self-test  

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christophe.p
(@christophe-p)
Miembro Moderator
Adding skip detection during firmware self-test

Hi,

I just had some issues with X-axis skipped steps, which were fixed by going to power mode. Meanwhile I found that my cork tile used for heatbed insulation moved a bit, touching the Z frame.

However I would find useful to see a diagnostic test added to the self-test feature of the Printer, with this basic algorithm:

  • home X and Y axis, set to silent mode.

  • Do some movement on X axis, then on Y axis with small acceleration. Go back to origin, check if both endstop are triggered at position 0. If not, it means that some steps were skipped.

  • Loop these actions several time, increasing acceleration at each iteration.
  • Would this makes sense ? Would you like to see that implemented ?

    I'm like Jon Snow, I know nothing.

    Respondido : 22/07/2016 10:58 pm
    PJR
     PJR
    (@pjr)
    Antient Member Moderator
    Re: Adding skip detection during firmware self-test

    Christophe

    That would be a real pain in the a55 and slow things down a lot for me; I only ever use High Power mode and I set the firmware so that both modes use the same settings.

    Sorry... 😥

    Peter

    Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

    Respondido : 22/07/2016 11:06 pm
    David T.
    (@david-t)
    Noble Member
    Re: Adding skip detection during firmware self-test

    This process is good for finding out physical limits of each particular printer, but doesn't help in case the steps are lost because of head stuck on warped object, for example.
    As far as I know, PR is going to implement some sort of stalled steps detection directly into electronics of printer. Lets wait and maybe get surprised. 😉

    Respondido : 22/07/2016 11:12 pm
    christophe.p
    (@christophe-p)
    Miembro Moderator
    Topic starter answered:
    Re: Adding skip detection during firmware self-test

    @Peter, You don't have to feel sorry ^^

    However since it should be implemented in the self-test feature, the one you usually only run once you finish the printer build, I do not think it would impact your printing routine. Do you use this feature on regular basis ?

    Setting the printer to quiet mode before this test is a good way to put the printer in condition where skipped steps are proned to occur if you have a build issue. But it should not change the preference for regular print.

    @David

    If PR implements it, that would be just perfect :). But I'm a bit curious how it could be possible during a print. Does the steppers return a status if a step is missed ?

    I'm like Jon Snow, I know nothing.

    Respondido : 22/07/2016 11:14 pm
    David T.
    (@david-t)
    Noble Member
    Re: Adding skip detection during firmware self-test

    Does the steppers return a status if a step is missed ?
    http://lmgtfy.com/?q=stepper+motor+driver+stall+detection

    Respondido : 22/07/2016 11:26 pm
    kevin.b2
    (@kevin-b2)
    Trusted Member
    Re: Adding skip detection during firmware self-test

    I too have been seeing skipped steps when using silent mode, but it does not happen super regularly so i'm not sure this test would catch it OR the test would be very long just to show that there is a problem.

    What are the differences with silent mode, just motor driver current? Can this be tweaked in future firmware revisions?

    Respondido : 23/07/2016 3:23 am
    PJR
     PJR
    (@pjr)
    Antient Member Moderator
    Re: Adding skip detection during firmware self-test

    Kevin

    The difference is the motor current settings only. It is easy to amend the firmware (when the source is available) to your own requirements.

    Peter

    Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

    Respondido : 23/07/2016 10:04 am
    kevin.b2
    (@kevin-b2)
    Trusted Member
    Re: Adding skip detection during firmware self-test

    I'll give tuning the firmware a shot when i have a chance, but i'd like to point out that "my requirements" aren't unique or specific to my use case - i am just looking for the printer not to skip when in silent mode and it seems like others have this problem too 😀

    Respondido : 26/07/2016 12:35 am
    PJR
     PJR
    (@pjr)
    Antient Member Moderator
    Re: Adding skip detection during firmware self-test

    Kevin

    Due to manufacturing and build tolerances, the power your motors will require to prevent skipping in quiet mode will be different to most others. It will be a case of adjusting the motor power a bit at a time until the skipping stops.

    I think you may be able to use M907 to adjust the power settings on-the-fly to test what you need.

    For reliability, I always use the High-Power mode.

    Peter

    Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

    Respondido : 26/07/2016 9:19 am
    3Delight
    (@3delight)
    Moderador Moderator
    Re: Adding skip detection during firmware self-test

    Maybe it would be enough to add an extra setting in the Power Settings? At the moment we have low power Silent Mode and full power Hi-Power Mode, so maybe if the added a Normal Mode with all the sittings roughly half way between the two it would allow more choice? I've called it Normal Mode because the two available right now are the extremes so it would be nice to have a medium, balanced setting! Make it the default in the firmware and it gives people the chance to experiment if they want to... Just an idea 😳

    Respondido : 26/07/2016 3:35 pm
    kevin.b2
    (@kevin-b2)
    Trusted Member
    Re: Adding skip detection during firmware self-test

    Peter - Thanks for the explanation! That makes tons of sense. Although i do understand how the builds vary, i would expect silent mode to work for >90% of cases and it seems to be far less from the anecdotal stories we've heard online.

    I realize Prusa may want to keep silent mode as silent as possible (thus its name 😀 ), but it would be helpful to have a slightly quieter setting from High Power. I think 3Delight's suggestion for a "normal" power mode would be pretty cool to have!

    I'm going to play with the firmware soon, but i'm far from an expert so who knows what will happen 😛

    Respondido : 26/07/2016 5:21 pm
    PJR
     PJR
    (@pjr)
    Antient Member Moderator
    Re: Adding skip detection during firmware self-test

    Kevin

    Unfortunately most "happy customers" do not tend to post very often on the forum so it does tend to exaggerate the problems.

    For those who need a "balanced" setting, 3DD's suggestion is indeed a good idea.

    With regard to the firmware, 3.0.6 will be with us shortly, I would advise not to start looking at the firmware until the source code for that is released.

    Peter

    Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

    Respondido : 26/07/2016 5:43 pm
    David T.
    (@david-t)
    Noble Member
    Re: Adding skip detection during firmware self-test

    Maybe it would be enough to add an extra setting in the Power Settings? At the moment we have low power Silent Mode and full power Hi-Power Mode, so maybe if the added a Normal Mode with all the sittings roughly half way between the two it would allow more choice? I've called it Normal Mode because the two available right now are the extremes so it would be nice to have a medium, balanced setting! Make it the default in the firmware and it gives people the chance to experiment if they want to... Just an idea 😳
    I would rather see some full scale option, with silent mode as default (which works excellent for me by the way) and slider for power boost from 0% to 100% (0% = silent mode, 100% = Hi-power mode) separately for each axis. This type of setting would satisfy any user.

    Respondido : 26/07/2016 6:03 pm
    Vojtěch Bubník
    (@vojtech-bubnik)
    Miembro Admin
    Re: Adding skip detection during firmware self-test

    First, I like the idea of Christophe, doing a self-test verifying skipped steps. Actually I had a similar idea recently :-), but not for fine tuning the silent mode, but for the self test, to verify, that the machine does not skip steps anywhere in its working space.

    We plan to tune the envelope parameters (maximum velocity, acceleration and jerk) for the silent mode to make the silent mode more reliable. Still if your print lifts up, you will more likely have failed prints in the silent mode than in the power mode.

    Vojtech

    Respondido : 26/07/2016 7:08 pm
    Josef Průša
    (@josef-prusa)
    Miembro Admin
    Re: Adding skip detection during firmware self-test

    We fixed a bug in the marlin planner that probably caused 90% of the misaligned layers on the MK2. Well, we thing we fixed it. Vojta will know more.

    BTW. We just got a sample of a new board with drivers which can detect stall 🙂 But it is a long way from prototype to the production. Making printers without endstops will be awesome 🙂

    Founder and owner / Majitel a zakladatel
    Respondido : 26/07/2016 7:19 pm
    3Delight
    (@3delight)
    Moderador Moderator
    Re: Adding skip detection during firmware self-test

    Great news Josef.

    Can you say anymore about this new prototype board/drivers, like the make and basic specs?

    Respondido : 27/07/2016 10:28 am
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