i wasn't clear enough sorry. What i figure is to do a VB program wich will do the the whole calculation for you with a specified range and increment of Millibar or Meter value. Once the calculation are done, this program will store all result in a .BIN file. Once the file is created and saved to your hard disk, you use your EEPROM programmer to load this .BIN file into an external EEPROM attach to your PIC.

After that, your PIC will just need to read the value of the calculation to your EEPROM by using the millibar variable as a kind of 'EEPROM address pointer'

For sure a PIC can't run a VB program. But you can do a VB program that will communicate to your PIC via the COM port.

what is the range of your millibar value?
How many decimal you want to have in the result???

If you need any info about VB let me know in PM.