How should we wire the photoswitchs?

[kamocat]

We need to put a resistor in series, don't we? The 9403 can withstand a 30v signal, but use at this voltage will degrade the life of the module.
The standard voltage it specs is -0.5v to 5.25v.

If possible, I'd prefer to use an inline resistor, instead of a voltage divider. At 250 micro-amps, it would take a 34k resistor to drop the voltage from 12v to about 5v.

[Alan Anderson]

Originally Posted by kamocat

We need to put a resistor in series, don't we?

It looks like the output of the sensors is just like a Banner sensor's NPN output. It supplies no power. It is effectively an on/off switch that either connects the output to ground or leaves it open. The Digital Sidecar's inputs will happily take that input without modification; it's basically what they were designed for.

[kamocat]

Oh, okay. That's why they gave us NPN then. Cool!