Installing limit switches (not homing switches)

Can anyone suggest the correct way to wire a series of switches into the Controller so I can setup some true “limit switches”?

For those who’ve not seen the associated threads on this, the ‘limit switches’ supplied with the X-Carve are not actually “Limit Switches”, they’re actually 'Homing Switches". If you’ve got them fitted, try operating one with your finger while the machine is operating and you’ll see that they do nothing to actually stop the machine while it’s in use. They’re only used when “Homing” the machine via GCode commands (at least this is my limited understanding of the process anyway).

What I’d like to do is to fit a switch to each end of the X and Y axis (and probably the top of Z) and to somehow wire them into the controller in such a way that the operation of any switch brings the stepper motors to a stop.

What I’d need answered is:

  • How do I wire these into the Controller?
  • I assume I’ll grab a bunch of NC or NO switches and wire them in series, but I suspect theres a more elegant way to wire them into the Controller than to just crudely interrupt the power somewhere.

Any suggestions would be appreciated.

David.

I installed the switch kit with my 1000mm X-Carve. They work well. To add additional switches to my X and Y axis I tied the two X-Axis switches together and the Y-Axis switches together.

On the controller board for GRBL version 0.9i use Pins 9, 10 and 12. The connection is on this page: https://github.com/grbl/grbl/wiki/Connecting-Grbl

Make sure you use the version for 0.9.

You also need to turn the switches on in your GRBL settings.

See this page for that:

Thanks Erik,
As a non electronics person, I kinda understand, but not really…

  • Are these switches normally closed or normally open?
  • I assume operating one of the switches makes or breaks the connection between ground and the associated pin?
    i.e. connecting or breaking the circuit between pin 12 and ground will stop the Z axis?

According to the instructions they should be wired normally open.

Hitting any switch will stop all three Axis.