Jim,
1 ) Mount the switches. You may want to wire them before mounting them. Choose the wiring path carefully.
2 ) Connect the three home limit switches in series (X-NC to Y-C, Y-NC to Z-C) using the switch common (C) and the switch normally closed contact (NC).
3 ) The remaining X-C and Z-NC terminals will be wired to the input port. Nothing will be connected to the normally open (NO) contacts.
If you have a multimeter, use the ohms or continuity setting, test each switch and the three switches wired in series. The two wires coming from the switches to the port should appear shorted until you press any of the three switches. Then they should indicate an open.
4 ) Wire the switch X-C wire to the port ground.
5 ) Wire the switch Z-NC switch wire to one of the inputs. The input should be set-up for stopping all three axe (X, Y, & Z) with a positive signal.
6 ) Now get a 4,700 ohm (1/8 watt or 1/4watt) resistor. Any resistor value from 500 ohms to 20,000 ohms will work just fine. Lower ohms draws more current, and higher ohms allows more sensitivity to noise. If you need to buy one fast, Radio Shack has them locally for under $2. for a set of 5.
7) Connect the resistor between the switch input port (Z-NC) and the Plus 5 volt supply.
8 ) Monitor the port on the diagnostic screen, it should indicate that the port is at ground. When you activate any of the switches, it should go to plus 5 Volts and turn on the port indicator, as well as E-stop the machine.
9 ) If any of the daisy-chained switches or any of the wires are defective, the circuit will open and do an E-Stop.
10 ) Set the software de-bounce timing so that the switches do not trip under normal use from vibration. (try 200 & 100)
Hope this helps,
Bill