make chart with fixed parameters

Hello everybody,
Is it possible to insert in rslogix5000 a chart with fixed parameters that can be chosen regarding a tag value?
I make an example :
I have a gas and regarding the reading pressure I can understand the temperature by follow the enthalpy chart.
There isn't any formula can match the pressure and temperature ...
so, I need to copy the temperature/pressure chart inside the plc program and let it choose the most close value.

there are more than 80 parameters and to compare all it will be complicated and long file ..
DOES ANY ONE HAVE EASY SOLUTION ?
THANK YOU VERY MUCH FOR ALL SUGGESTIONS.
Graziano

What size is the chart? How many values are we talking?

You could do it easily with compare instructions such as GEQ, LES, etc. and Move Instructions.

Because your chart will only be "close", there are curve-fitting equations that can approximately duplicate almost any chart with a mathematical formula.

https://www.google.com/#bav=on.2,or.&fp=6893f97366b740c3&q=curve+fitting+software

I would look at the FSC instruction. (File Search and Compare)
Build 2 Arrays Pressure/Temp. The FSC instruction can lookup the Pressure and it will return the position in the array. Then use that position to look up your Temp in the Second Array. If you look at the example programs located in RS5000 Check out the BarCode Lookup Example. This will be simalar to what you need and may help you find a solution.