[Mikeee]

The G540 Inputs read approx. 11 VDC without connection (pullup resistors). I'm concerned about the required logic voltage level required for a valid low input. I've connected 2 proximity limit switches in parallel to the input. They are 2 wire NO model AM1-A0-2A. The leakage current of the switches drag the input voltage down to 9.5 Volts. When activated the operational voltage at input is 2.55 Volts. The Gecko is sending an active low signal to the Computer and Mach 3 sees the trip of the limit switch. Is this a safe voltage to feed to the input for active low? Current draw at active state is about 4 ma.

[chadcummings]

Did you ever get this working?

What did you end up doing?

[Mikeee]

It's been quite awhile since I posted that message .... but decided way back then to only use one of the proximity switches on each input. It works great. Didn't like how much 2 of them together loaded the circuit. Always meant to revisit it with 3 wire sensors to get more than one connected to an input. The damn thing just works so good it has not been necessary.

[chadcummings]

I found this configuration:

http://www.cnczone.com/forums/attach...8&d=1297903175

Is this along the lines of what you were thinking about?

[Mikeee]

Yes, that looks good. I purchased 6 of the 2 wire sensors which work great for home detect. So no need to replace them but might change the mechanical limit switches to 3 wire proximity sensors as in your picture. The benefit to the mechanical switch wired normally closed is that a broken wire will cause a limit input to trip. The two wire proximity sensor don't have that sort of safety feature.