Sorry to drag an old thread back from the dead.
We have a PNP optical sensor (
spec sheet,
manual) that for several reasons (time, money, size of the hole we need to drill) is really our only option. As I understand it, we need to A - wire directly to the PDB and B - use a pulldown resistor in between the signal on the sensor and the ground, and C - wire it through another NPN switch to make it work?