Hi folks, I just picked up several Xtension limit switches to replace some damaged micro switches. I originally had my switches Normally Closed. That way if the wire was damaged the machine would stop. My understanding was this is safer than Normally Open where a wire failure would not be caught. Am I missing something? Is there an advantage to using Normally Opened that I am not aware of? Also, is there a schematic for Xtension limit switches somewhere? Doug
Xtension Switches have onboard RC noise filtering, so no real need for normally closed. The main advantage is the default Grbl config is for NO switches, you need to first change $5-setting for NC switches. NO also allows easier wiring of the min/max switches as you can just parallel them - no need for complicated series wiring schemes
I think I'm going to run Xtension limit switches all the way around my machine. I also wondered if there's a wiring diagram, didn't find one, so made my own. See attached. I think it's this simple... hopefully somebody will confirm?
Not at this time, very simple though, switch wired NO with a 10k pullup , RC filter on SIGNAL line, and an Indicator LED
I am setting my machine up to use the dual axis homing feature in GRBL, which requires the switches to be wired in a NC configuration rather than NO, and using NO is not an option for me. Is there any way to wire these switches in the NC without having to solder the wires directly to the switch itself? I validated the switch itself could be used as NC... but unless there is solder jumper or something, it looks like the only option I have is to solder the wires directly to the switches to make it work. If there is not, it will be extremely disappointing as the more generic switches which were sold by openbuilds and no longer available didn't have this limitation, and the OpenBuilds Store makes no mention anywhere that these switches can only be used in a NO configuration.
That is not true. You can wire the Y2 switch in parallel to Z as normally open. Grbl relies on the homing order (z first, then XY to differentiate) Read the relevant sections of config.h Also, dual homing sounds good but its much easier to build the machine square from the beginning (we played with it a lot, in practice its harder to setup those to switches to be square
