NO/NC Endstops



  • I'm using the Duet on a CNC and had a question. Regarding the endstop wiring, can the core programming diferentiate between NO and NC wiring? Can you choose between whether you want the program to use endstop as NO or NC wiring?



  • @perseveranze said in NO/NC Endstops:

    I'm using the Duet on a CNC and had a question. Regarding the endstop wiring, can the core programming diferentiate between NO and NC wiring? Can you choose between whether you want the program to use endstop as NO or NC wiring?

    Yes.

    Frederick



  • If you look at the Endstop Configuration, you will see how to tells the Duet what type you have: https://duet3d.dozuki.com/Wiki/Gcode#Section_M574_Set_endstop_configuration

    "This defines the type of endstop switch or opto sensor that the printer has for each axis: 0 = none, 1 = low end, 2 = high end. The optional S parameter defines whether the endstop input is active high (S1, the default) or low (S0). A normally-closed endstop switch wired in the usual way produces an active high output (S1)."

    This command can be run twice (or more) if you have different types for different axis.

    On the Duet (and many other boards), the Normally Closed between Signal and GND is preferred. In NC configuration, it have the added benefit to detect if the switch is missing (in which case it will find an open circuit, same as when it is triggered and thus be able to prevent damage to the machine).



  • Yes, the Duet/RepRap is easily configured for open or closed.

    However...

    I am a very strong believer in Nclosed (and wired in series if there is more than one). This detects failed switches, broken wires, loose connections in so many ways that Nopen does not.

    (It is late, I'm tired, and I hope I typed that correctly, not backwards... you get the drift). 🙂


 

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