Newb: Z Home routine confusion Z Max endstp switch & BLTouch Min/Probe

  • Hello Duet folks … reluctant newbie posting - so please be gentle... 1st ever printer, First ever duet wifi ... Been at this particular hurdle for 10 hrs - figure its time to ask a question for some clarification ... the more reading I do at this point is just mucking up the works and causing more confusion. Have tried to locate a similar issue and solution in docs and forum but as of yet - no luck - will continue looking but in the meantime hope someone can lend an assist.

    Prusa i3 MK2s Zaribo Clone / Cartesian printer

    X / Y Homing based off the Wiki docs - working well … X Y endstops set and working as intended [ microswitches / NC …/ X min/low / Y Max / High ]

    Read about Print Resume feature needing a Max Z endstop - so I added one into the mix … [ Microswitch / NC / Z Max/High ]
    Z Max endstop switch triggers and registers in the web GUI interface as triggered when … triggered 🙂 However; it does NOT stop/Halt Z+ axis movement.

    BL Touch Smart Probe is setup as per the Wiki Docs - 3.3v trace cut ... it is working based upon the basic test routine on the wiki docs here :

    Probe deploys / lights go blue Z Probe shows [ "0" ] in GUI … Manual Z - steps via the GUI makes probe tip touches bed and triggers Web GUI registers [ "1000" ] … That is how I am so far defining it as "working" ...

    Created the deployprobe.g / retractprobe.g files as per the wiki - have yet to adjust the homez.g or homeall.g files yet ...

    At this point Im not sure which way to go to get Z homing routing configured without smashing the nozzle into the bed ... AND Im baffled currently as to why the Z Max endstop is NOT halting Z+ motion when triggered.

    Here's pertinent config.g sections :

    ; Configuration file for Duet WiFi (firmware version 1.17 to 1.19)
    ; executed by the firmware on start-up
    ; generated by RepRapFirmware Configuration Tool on Wed Jan 31 2018 09:50:41 GMT-0800 (Pacific Standard Time)

    ; General preferences
    M111 S0 ; Debugging off
    G21 ; Work in millimetres
    G90 ; Send absolute coordinates…
    M83 ; ...but relative extruder moves
    M555 P2 ; Set firmware compatibility to look like Marlin
    M208 X0 Y0 Z0 S1 ; Set axis minima
    M208 X220 Y220 Z200 S0 ; Set axis maxima

    ; Endstops
    M574 X1 S1 ; Set low-end [ min ] endstops || S1 = NC / Active High S0 = NO / Active Low
    M574 Y2 Z2 S1 ; Set high-end [ max ] endstops || S1 = NC / Active High S0 = NO / Active Low

    ; Z Probe / BL Touch Smart
    M307 H3 A-1 C-1 D-1 ; Set PIN Values on Duet Board for reassignment of Heater 3 for 3.3v BL Touch [ BL Tch Specific settings ]
    M558 P5 X0 Y0 Z1 H5 F100 T2000 ; Set Z probe type to [ unmodulated ??? ] || axes probe used on [ 1= in use / 0 = not in use ] || dive height || speeds
    G31 X0 Y0 Z2.5 P25 ; Set Z probe trigger value, offset and trigger height
    M557 X15:205 Y15:205 S20 ; Define mesh grid

    G31 and M557 - ripped offf str8 outta the docs - I have yet devised a plan to acquire the X Y Z offsets between the nozzle and BL Touch probe and the bed … trigger distance etc ...

    Thank you


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  • Thank you sir for the reply to my query … Yes I have seen and read thru that part ...

    Where I was mentally stuck was KNOWING the trigger distance and how to get that parameter into the configuration. What helped me move along - was finding this:

    Z is homing like a champion / BL Touch Smart is doing its thing and Im getting pretty decent repeatable trigger distances\ activations.

    Im sort of a "literal" and visual learner - yes I knew the inference to obtain that trigger height "somehow" was a known procedure but .. . In the future it may be helpful for newer folks to indicate a link to the above page from some of the Z probe/BL Touch wiki docs. Stumbled across it in a search … and its likely I missed the link in the myriad of docs I reviewed trying to sort it all ...

    It was actually on the main homepage - lol - but I was sooooo deep into the homing and BL Touch docs - I didnt go back to main wiki home for that ... guess its on me ...

    All in all - great docs/wiki ... Very pleased with my Duet wifi purchase and the documentation thereof ... Thanks for all you do !

    Now its off to Mesh Bed Leveling 🙂

  • Alrighty then … moved passed some my issues .. but a few small nagging items in this vain - left to resolve.

    Z Max endstop with a Z probe ... Z max endstop registers in the software as working Active High / NC switch ... light on z axis clicks OFF when switch is activated ... however; when testing by doing a long z+ move ... say 100+ off the z home position, triggering the switch .... do NOT stop the Z+ axis movement... I suspect my config.g settings for both a Z probe AND a Max endstop switch or incompatible - but Im not finding docs on how to run both.

    Z probe as min / low - endstop ? How...

    Also, Im finding nothing useable in the area of how to determine the x/y horiz offsets between PROBE and Nozzle

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