1771 IFE A Card Scaling

I have a PLC 5/30 with a 1771 IFE A card that I am reading a temperature input on. The temperature sensor is a 4-20 that will read temp from 0-100 celcius. The scaling had a default value of 0 for raw min and 4095 for raw max. My temp appears to be a few degrees off... For applications like this do I just adjust the raw max until temp corresponds to actual? I do not have a clear idea on how scaling works. I have heard you sometimes need to do the math to figure it out. Any help with what the equation is or if I am correct in just adjusting would be appreciated. I would like to be able to pinpoint with a formula if that is possible.

Thanks

Simple algebra ...

y = mx + b

or in RA terms

Out = (In-InRawMin) * ((InEUMax - InEUMin)/(InRawMax - InRawMin)) + InEUMin.

here's a former post that might help with your situation ...

http://www.plctalk.net/qanda/showthread.php?p=29643&postcount=11

if you can give us more information, then we'll be able to give you more detailed help ...

one thing that would be VERY helpful is a series of DATA POINTS ... the more of these you can give us, the better it will be when we answer ...

RANDOM (meaningless) examples:

4 mA = 0 data = 0 degs C actual
12 mA = 2048 data = 50 degs C actual
20 mA = 4095 data = 100 degs C actual

once we have REAL data like that, then we can easily calculate the "correlation" and tell you whether your system is "linear" (which would be good) or "not linear" (which would be bad) ...

another question that hasn't been answered so far is this: do you have any "math functions" in the ladder program which manipulate/calculate these signals? ...

suggestion: post your .RSP file and let us take a look ...