How to make a room pressure/condition monitor display the proper room condition

My room pressure/condition monitor is not displaying the proper room condition, how do I make it show a positive, negative or neutral room?

For critical environments, the space being monitored can be a positive, negative, or neutral space. The user determines what kind of space is being monitored with the alarm set points. A positive room will have alarm set points set above 0. A negative pressure room will have alarm set points below 0. A neutral room will have the alarm set points span both sides of 0 pressure.