Additional limit switches (Over and above XYZ homing switches)



  • Hi Guys. Thanks for the input but perhaps it’s my inexperience with the duet controller. I’m still not sure from the various articles where I plug in the wires in series for the limit switches. Is it into the next vacant output on the board? XYZ being used for homing. Sorry for being a pain.



  • @trev133 said in Additional limit switches (Over and above XYZ homing switches):

    Hi Guys. Thanks for the input but perhaps it’s my inexperience with the duet controller. I’m still not sure from the various articles where I plug in the wires in series for the limit switches. Is it into the next vacant output on the board? XYZ being used for homing. Sorry for being a pain.

    Yes pretty much. Assuming you want these switch to do something like an emergency stop if triggered (that's what I do BTW) then you use M581 to detect the trigger and act accordingly. In my case I have an emergency stop button (NC switch) connect to E4 and the limit switches wired in series and connected to E5. So in my config.g I have:

    ; Emergency stops
    M581 E4 S1 T0 C0 ; E4 is emergency stop button, S1 = rising edge, T0 is emergency stop like M112, C0 means any time
    M581 E5 S1 T0 C0 ; E5 is axes limits



  • @deckingman That’s brilliant, Thank You.



  • Hi guy's just one more point. When I go into config. g there is no line item equating to M581. Do I just add this line with relevant factors and is there any precedence where it should be placed in the file?
    Thanks again



  • @trev133 said in Additional limit switches (Over and above XYZ homing switches):

    Hi guy's just one more point. When I go into config. g there is no line item equating to M581. Do I just add this line with relevant factors and is there any precedence where it should be placed in the file?
    Thanks again

    Yes, just add the line and it can go pretty much anywhere in the file. I have my M581 lines at the end of my config.g just because they are sort of "extra commands" so I know where to find them if I need to edit them.

    What happens when you turn on the machine is that the config-g file is read and commands are carried out in sequence from the start of the file so it generally doesn't matter what order they are in. The exceptions to this rule are things like like axis mapping and micro-stepping in conjunction with steps per mm but that's not important for what you need to do here.

    The configuration files, including config.g and macros etc are simple text files so you can use any text editor to modify them. I use notepad++ which is free.

    HTH



  • Ian that’s good info. Thank you
    Trevor



  • @deckingman said in Additional limit switches (Over and above XYZ homing switches):

    Yes pretty much. Assuming you want these switch to do something like an emergency stop if triggered (that's what I do BTW) then you use M581 to detect the trigger and act accordingly. In my case I have an emergency stop button (NC switch) connect to E4 and the limit switches wired in series and connected to E5. So in my config.g I have:
    ; Emergency stops
    M581 E4 S1 T0 C0 ; E4 is emergency stop button, S1 = rising edge, T0 is emergency stop like M112, C0 means any time
    M581 E5 S1 T0 C0 ; E5 is axes limits

    Just about to configure Endstops in config. g as advised. Just checking: I have NC switches connected to point E0 on Duet.
    Do I code it M581 E0 S1 T0 C0 or is it M581 E4 S1 T0 C0



  • @trev133 You need to configure the end stop that you have physically connect the wires to. So if the wires are physically connected to E0 then use M581 E0 etc. The available connections on the Duet main board are Z, Y X , E0 and E1. https://duet3d.dozuki.com/Wiki/Duet_Wiring_Diagrams . End stops E2 to E6 are on the Duex5 expansion board (which I happen to use).



  • Thanks Ian. That’s what I thought. Trevor



  • Just configured it. Works a treat Ian. Thanks for all your help. Really appreciated. Trevor



  • Hi Again. Want to set up an XYZ probe as per the Ooznest website. It parallel connects to the Z end stop point on the Duet. Appears it will only work with Normally Open limit switches. Question is, If I change my homing limit switches to Normally Open to suit the probe, can I retain the setup up as above for my limit switches at other end of bed which are in series NC and set up as above using Code M581 and connected to End Stop output E0. Trevor



  • @trev133 said in Additional limit switches (Over and above XYZ homing switches):
    ..........................Question is, If I change my homing limit switches to Normally Open to suit the probe, can I retain the setup up as above for my limit switches at other end of bed which are in series NC and set up as above using Code M581 and connected to End Stop output E0. Trevor

    Short answer - yes.

    Longer answer - the axes maxima switches connected to a spare end stop (E0) and set to trigger an emergency stop using M581 work independently of anything you have set up for "normal" homing using axes minima switches or a probe.

    Caveat. I don't know anything about the XYZ probe you mention but can't think of any reason why it should interact with those axes maxima switches.



  • Thanks Ian, that's good news. As always really appreciated.
    Trevor


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