NOTE: The yellow/green displays have been discontinued. The current displays are gray with white lights, which are more pleasing to the eye.

The PS-525 displays altitude in feet and meters, as selected with the "UNITS" button. Both feet and meters are displayed along with their vertical speed component.

The PS-525 tester displays altitudes in 1-foot increments up to 20,000 feet; 2-feet increments between 20,000 and 30,000 feet, and 5-feet increments above 30,000 feet; or in 1-meter increments if it is in the metric mode. The Vertical Speed Indication also increments by 25 feet or 10 meters. The VSI section will display an up or down arrow, depending on the direction of altitude change being sensed.

Accuracy will vary with altitude:

-1500 to 10,000 ft ..........+/- 5 ft

10,000 to 20,000 ft .........+/- 15ft

20,000 to 30,000 ft .........+/- 20ft

30,000 to 40,000 ft .........+/- 30ft

40,000 to 50,000ft ..........+/- 40ft (PS-525A version)

The vacuum pumps internal to the PS-525 tester will draw sufficient vacuum to go up to at least 35,000 feet (10,700 meters).

A PS-525A version is available, and goes up to 50,000 feet. This model uses stronger vacuum pumps and additional programming to extend the calibration values up to the higher altitudes.

The PS-525 displays airspeed in MPH, or KPH in increments of 1, and Knots in increments of 0.1. The Knots display will indicate from 20 up to 650 Knots, MPH will indicate up to 748 MPH, and the KPH will display from 34 to 1204 KPH.

By pressing the Units Select button, the choice of speed can be changed to KPH/ Knots or MPH/Knots.

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.

Both the Altimeter and Airspeed displays have a leak check feature. This feature may be activated when in the Altitude mode or the Airspeed mode. There is no leak check function in other modes.

The initial pressing of the "Leak Check" button will enable a 120 second timer. Successive pressing of the "Leak Check" button will subtract 30 second increments from this time. Once the desired time is selected, the "Units" button is pressed to begin the timing. Pressing the "Exit" button will exit the Leak Check function.

While in the Leak Test mode, the display will indicate the gain or loss experienced during the test time period. When the timer reaches 0 seconds, it will stop calculating the loss, and will hold the value in the display until the "Exit" button is pressed.

The PS-525 test box contains a built-in altitude encoder reader for displaying Gray Code, and two separate, selectable RS232 inputs at speeds of 1200, 2400, 9600 baud. To select the disired reading code, the operator presses the "Select Code" button under the Decoder display, until the desired code is selected. Then the display will either read the signal, or display a message that the signal is not there. Gray code lines A, B, C, and D can be read independently by pressing the Select Code button to this function.

The connector pin-out on the front panel is identical to the pin-out of the popular ACK A-30 encoder. In fact, this encoder can be plugged directly into the connector if desired. Test cables can be built to extend the connector and test the encoder in the aircraft. In addition, adapter cables can be made to test all other encoders on the market. (Cables and adapters are not included in the sale of the box.)

The batteries internal to the PS-525 tester can power altitude encoders at either 12 or 24 volts. The desired voltage is selected by the toggle switch when the operator applies power to the test unit.

The Encoder Reader is compatible with outputs of the following altitude encoders:

ACK (gray code, 1200, 2400, 9600 baud)

Shadin (gray code, 9600 baud)

Trans-Cal

Ameri-King (gray code)

The Encoder Reader is compatible with the following RS-232 protocols:

Garmin 1200, 9600 baud

Northstar 2400 baud

Shadin 9600 baud

UPS AT 1200 baud

Trimble 9600 baud