Chapter 4. Using Special Features70 Model PM880 Portable Hygrometer User’s Manual4.10 Entering Reference DataWARNING! DO NOT CHANGE THESE VALUES UNLESS INSTRUCTED BY GE TODO SO.The PM880 requires reference values for its measurement circuitry formoisture and pressure inputs. The references are factory calibration values.These values can be found on the label located inside the batterycompartment.If instructed by GE to change these values, use the following steps.1. If the menu is not active, press [MENU].2. Use the arrow keys to scroll to Service and press [ENTER].3. Use the arrow keys to scroll to References and press [ENTER]. Thescreen appears similar to Figure 30.Figure 30: References Window
