Quote Originally Posted by Stevenson View Post
On the attached diagnostic screen where I have the two red arrows pointing what it means the M4++Limits and M4Home? Do they refer to a motor, axis or what?
Yes, they refer to the 4th axis or motor output. If you are slaving motors with the 4th axis then usually you would turn off the LIMIT++/-- in ports and pins but leave the HOME input so can home. In this case, the M4 will light up when homing and then go off after the axis as backed off the switch, which I think is probably what's happening in your case but you have the LIMIT turned on and using the same pin number so the M4++ lights up as well.
In which case this would be correct when homing if the Home SW. safety button is not set in the General config screen while homing. If the Home SW.safety was ticked you would get a Limit tripped error.

Edit: Ignore this I can see it's been answered. It's been several weeks since I've been on here and this showed as a current post on my system.?