Easy Q regarding input wiring on G540

[BanduraMaker]

I made a simple little pendant with E-stop, Cycle Start and Feedhold using a little industrial button box I found on Amazon to help control my machine.

All of the buttons have both normally open and normally closed terminals and I decided that I didn't like the idea of floating inputs so I have them all wired to the normally closed terminals tying the input line to ground and I open the circuit to trigger the Cycle Start or Feedhold buttons in Mach (using inputs 3&4 on the G540). E-stop also uses the NC connection on the e-stop button.

My pendant works just fine and I'm just floating this question to see if anyone has any compelling reason to do the opposite and close the connection to ground to activate a switch rather than the method I'm using.

TIA,

[rowbare]

Anything that stops the machine such as limit switches and E-Stops are best wired normally closed. That way if a wire breaks/disconnects it defaults to a safe condition. As for anything that starts the machine, I would suggest using the normally open contacts so a wire break/disconnection won't start the machine unexpectedly.

bob

[BanduraMaker]

Excellent point! I'll get that re-wired tonight.