Stupid question of the day

Just a quick one, i want to use a 2wire proximity switch to signal an input of a SLC500

voltage 110vAC
i/p card is a 1746-AI16

proximity switch is a AB 872CA10N18A2 which the AB web site states a miminum load of 5mA

Now the AB web site states that the i/p card has off state maximum current of 2mA but my suppliers catelogue states an input current of 12mA

I'm tempted to buy one and test it before i decided on my design, but im sure i've seen 2 wire AC proximity switches connected to PLC inputs before

I guess i could used a pull down resistor to increase the current through the prox?

The input current of 12 ma may be what is needed to establish the full ON state. But you are correct in judging that the minimum current needed by the prox will be such that the input state may not turn off. Either a pull down resistor or an intermediate relay may be needed.

And it's not a stupid question.

Yes this is a problem with most Prox switches, The input won't turn off. For 120 AC I use Pepperl & Fuchs NJ20+U4+W, their leakage current is 1.7 mA.
It's usually easier to match 24 VDC.
Roy