Limit switches always triggered



  • Hi, so today I am messing around with switches. I am using these limit switches:
    https://openbuildspartstore.com/xtension-limit-switch-kit/ (Configuration Normally Open)
    wired to the Duet WiFi running firmware 3.0 on a CoreXY printer, but when using the Configurator I clicked Active High and I got this config g:
    M574 X1 S1 P"xstop"
    M574 Y1 S1 P"ystop"
    M574 Z1 S1 P"zstop"
    so all the switches were triggered and I couldn't home the the axis. So when I held the switch down - the motors would start homing. I used the Configurator (because I am still learning what G-code does) again and changed to Active Low and I got this config g:
    M574 X1 S0 P"xstop"
    M574 Y1 S0 P"ystop"
    M574 Z1 S0 P"zstop"
    but after changing those values the switches were still marked as triggered in the web control menu. So I stopped being lazy and found this:
    Endstop type S0 (active low switch) is no longer supported in M574 commands. Instead, use type S1 and invert the input by prefixing the pin name with '!'.
    So in firmware 3 there is no S0? However there is no example of how that looks in G code
    is it like this - M574 X1 S1 !P"xstop"
    I just don't want to mess around and break something. Ask first, break later!
    Also if this is what the error actually is - that means the Configurator is not making proper setting for those using firmware 3 specifically for the endstops.


  • administrators

    That web page says "Input Voltage 5-24v". This is very surprising, given that 5V is used by older 8-bit electronics, and modern 32-bit electronics uses 3.3V. So on the face of it, those switches are only for use with electronics that can be considered obsolete, and are not suitable for use with Duet and other modern electronics. However, as it is a mechanical switch, it's likely that it will work with 3.3V; except that if it has an LED on it, the LED may light up rather dimly.

    How have you connected the 3 pins on it to the Duet?

    What components does the endstop have on it, apart from the microswitch?



  • Oh pff, and I bought them because I thought they look fancy. serves me right. Should have bought something smaller anyway, they are too long and stick out.
    I don't know what other components can there be on it, honestly. They seem to work. The LED is visibly flashing when they are triggered. Everything is connected on the Duet. Stop/3v/ Ground (on the switch stop is marked as signal if that helps) I used this picture because it is inconvenient to go the back of the duet every time :
    https://d17kynu4zpq5hy.cloudfront.net/igi/duet3d/vqBUAZPsxMC5tRgt.huge



  • @id104335409 If you don't find a resolution and cannot use the limit switches, instead of being stuck or tossing them, I can trade you for switches that I have that work on the DUET. I have a CNC mill that uses an Openbuilds controller.



  • Found it:
    M574 X1 S1 P"!xstop" that ! turns normally closed switches to normally open (active high to active low)
    successfully homed
    hope that helps someone else as well


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