Wiring home and limit switches

[JAZZCNC]

Hi Dan,

The way it's done is to series wire the E-stop and limits thru the 24V coil (coil not contact) of a relay. Then take the +5V signal from the BOB and run thru the contact of same relay and back to -5V on BOB.
This then informs Mach an Estop has happened so stop the G-code from running.
Inside mach you just set inputs up to watch same pin for both e-stop and limits. This does mean fault LED's in Mach will show both E-stop and limits tripped at same time. If you want to know which individual switch tripped then only way round this is to use an input for each switch. Has you can see this will need many inputs which you don't have and In practice this doesn't matter much has you'll know what's caused it.

The other contacts of the relay can then be used to either control other relays or directly turn something off IE: 70V supply.

Home switches shouldn't be run thru relays has the delay is too long and makes them inaccurate. Just use the 5V signal from bob for relays has your only using it when homing so very rarely do they get affected by noise etc so ok to do so.
They can also be wired in series and just use 1 input has Mach only homes one Axis at a time and actually doesn't care where the switch is pressed because it just records the coordinates for the Axis it's referencing at the time when it see's the input trigger then does the same again for next Axis when sees input trigger again.
In theory and practice when wired in series you can set the home position for X axis by pressing Z or Y axis switch because it just records the position it's at for Axis it's referencing when input fires.

Note If your using 2 motors slaved to an axis then you must have each motor on separate inputs. One can be wired in series with other axis but the other must be on it's own separate input. If not then Mach can't individually home each motor for squaring gantry.