I am monitoring a number of channels in non-differential mode on a 9205. One channel I want to use to monitor an external switch. If under 1V I do one thing, if over 1V I do another. This is hooked to a SPDT switch. The signal pin I monitor is on the common pin. I wire another pin to COM on the 9205 to pull the signal down when the switch is in one state.
How can I get the signal to pull up above 1V when the switch is in the other state?
Possibilities:
1) Wire the other switch pole to a positive reference out from the 9205. But it does not seem to have this.
2) The 9205 has an internal pull up so when not switched to COM it will float high. But that does not seem to be what happens. The pin seems to float.
3) Provide my own pull up resistor to my own voltage source. But I would really like to not hook up more resistors. Just adds more wires to go wrong. I also need to make sure my signal does not exceed +10V and what I have is a +15V source.
4) Wire the other switch pole to DO0 and drive it high in software. A bit ugly and adds some more software, but a doable solution.
Ideally #1 would be my preferred solution but there does not seem to be a nice +10V reference voltage available (or anything above 1V) like there is a COM (0V) available for this.
