[Alan Anderson]

Limit switches are typically connected between the ground and signal pins of a digital input on the Robot Controller. On a standard PWM cable, that's the black and white wires; the red wire is not used. Use the two contacts on the limit switch that are an open circuit when the switch is not active, and a short circuit when the switch is active. The switch I have handy to look at labels those contacts COM (for "common") and NO (for "normally open"). The software will see a logic 1 on the input change to a logic 0 as the switch is activated.

You can also use the COM and NC ("normally closed") contacts instead. That will result in a logic 0 when inactive and a logic 1 when active. It will also give a logic 1 if the wires to the switch come loose, which might be either a good or a bad thing depending on what the software does with it.