I'm using a ratiometric sensor with an NI WSN-3202 node, and I'd like to be able to know exactly what voltage the node is providing as excitation so that I can properly determine the sensor reading. Is there any way to read out this value? I know it's supposed to be 11.5-12.5 volts, but that's an awfully big range and I'd like to know what it actually is.
Are you using all of your analog channels?
Why not use one of them to measure the excitation voltage?
If you measure the voltage once, it should remain pretty steady. However, it can drift with operating temperature and the like. I believe the wide spec is due to the tolerance of the hardware and you won't really see that full range with your specific node.