I'm sure one of you out has been through this before.
I have a 1746-NIOV analog I/O module(10vdc to 0: -32768 to 32768) with an LM235 Ambient sensor -40 to 125 C
+5vdc power source
The problem i'm trying to figure out is how i can scale the input from the sensor to degrees F when the power supply voltage is constantly increasing and decreasing.

Example: 5.205994 to 5.197754
(Using :10V / 32768 * Input Value)
Is there an easy way to do this?

The power supply should be just powering the temperature probe and should have no effect on the reading. Most power supplies have a natural flucuation and as long as it stays within the range, it will not affect your probe. What you need to do is take the 0 to 10V out of the probe and feed that to the card (Ex: I:0.0). Use a SCP instruction and set the input min to 0, the input max to 32767. The scaled min to -40 and the scaled max to 125.

Oops. Convert the -40 and 125 to F and use those number in scaled min and scaled max.