I have set up my spindle control in mach 3 and I can turn it on and off by pushing the spindle button on the Mach 3 screen.  I would also like to add another safety control to the spindle via a selector switch connected to a input.  This switch would lock out the spindle control.  I have assigned it to an input but don't know how to program it to disable the spindle output.  Can anyone help me out?

hi i can help you please tell me exact wat you need

do you have internet so i can mange properly

Yes, I do .  What I am trying to do is to put an active low signal on input #1 (or any other input that will work) which will lock out the spindle relay connected to output #1

Your basically adding a software control as a safety for another software control. Imo, you should really have a mechanical switch to lockout your spindle, if it's purpose is a safety switch.