Both the Altitude and Airspeed displays can be set to display pressure in inHg, mbar, mmHg, and PSIA. These pressures are read directly from the sensor on the selected side.
The E.P.R. (Engine Pressure Ratio) is a reading that is the mathematical result of HighPressure/LowPressure, and is displayed only on the Airspeed side.. The PS-525 will display the low pressure, the high pressure (both in PSI), and the resulting EPR.The ratio values have a range from 0.07 to 6.00. Refer to the Operation Manual for more information.