1.1-17 Normal Value Reference Index

Displays should contain reference(s) to the values of normal operating condition(s).

Additional Information:
With references showing normal parameter operating values, the users are more likely to notice deviations from normal conditions. In such cases, the index might be displayed as a horizontal or vertical line, or perhaps as a reference curve of some kind. For example, a horizontal line representing normal operating conditions should be superimposed on the display.