New to the forum and I've just completed assembly and modification of a Chinese CNC Router. I have limit switches mounted now on 2 on X, 2 on Y and 1 on the top of Z, but I can't figure out how to wire them to my Chinese 0.9j GRBL board. I have looked at many diagrams for wiring in series, but my GRBL Board has 3 pins on each of the X,Y and Z limit inputs. These are marked + - and S on the backside of board. Can anyone suggest how I should wire a Normally Closed circuit to this with my 5 Micro Switches, please.....? Image of mystery board attached with Limit Pins to the right of image. Many thanks in advance, Adam
I am not familiar with that board. Have you tried the manufacturer's customer service yet? They may be in the best position to help you.
I don't know that board either but the 3rd input pin (S) must be the signal pin and would be used together with the +/- pins for an optical sensor connection. If you are using micro-switches however, then just use the S and ground (-) pin, the "S" to "normally closed" on the switch and ground to "C" on the switch. Just do not wire it wrong ( keep away from the + pin - that's for the optical sensor) Have a look here at the series and parallel switch wiring.. gnea/grbl
Thanks for your advice. I've connected 1 micro-switch as you suggested and it's now working. To get left and right limits on X Axis, should I connect Micro-Switches together via COM pins, and to -, and wire both NC pins together into S on the board? Many thanks, Adam
For Normally Closed switches you need to wire two switches on the same axis in series - signal (control board) to nc (switch one), common (switch one) to nc (switch two), common (switch two) to ground (control board) Alex.
Can't help with that one @Christian James, but hopefully someone who is familiar with that set-up will clarify that before someone tries to use that diagram. I think @sharmstr has used an arduino and may be able to help. Alex.
Yes Peter, that confirms what I thought and how mine is wired. Pin 11 has been grabbed for use by the spindle while the Z switch pin has been shoved onto pin 12
