Chapter 4. Using Special Features54 Model PM880 Portable Hygrometer User’s Manual4.7 Entering Constants and User FunctionsThe PM880 enables you to enter two types of constants, a user constant anda saturation constant, as well as user-defined functions and tables tomanipulate data.A user constant is a fixed value that is used to multiply the moisture ppmvalue (K PPMv). A saturation constant is used to calculate PPMw innon-aqueous liquids. If you do not know the saturation constant of theliquid, contact the factory.To extend programming capability, user functions enable you to program upto 8 mathematical equations. The PM880 also enables you to enter up to6 tables of non-linear or empirical data to support user function equations.This section consists of the following information:• Entering a User Constant - page 55• Entering a Saturation Constant - page 56• Entering User Functions - page 58• Setting Up User Tables - page 62
