Calibration Procedures; Altimeter Calibration - PRESTON PRESSURE PS-500 User And Maintenance Manual

CALIBRATION PROCEDURES

The recommended calibration interval for the PS-500 test box is one year. If at any
time during regular use the unit becomes unreliable or out of correct operating
calibration, it must be repaired and/or re-calibrated before continuing its use.
The PS-500 test box is easy to calibrate. There are 5 set points used in the calibration of
the altimeter side. Calibrating at multiple setpoints enables the altimeter to have a greater
degree of accuracy, allowing it to self-correct to the nearest calibrated set point.
The altimeter side should normally be calibrated first, as the airspeed side reads the static
pressure through the altimeter circuitry. However, if the altimeter side has been tested
and found satisfactory, the airspeed side can be calibrated at any time.
Note: the calibration factors are stored in the microcontroller's EEPROM memory. This
memory does not need battery back-up. The calibration will not be lost if the unit's
battery is disconnected or replaced.
PS-500 Altimeter Side Calibration Procedures
1. Apply power to the PS-500 and allow unit to warm up for a minimum of 10 minutes.
2. Gently close the Vacuum Control valve, Vacuum Vent valve, and Crossbleed valve.
3. Connect a known altitude pressure standard to the Vacuum Port.
4. Set the PS-500 altimeter measurement units to read in mbar by pressing the Units
button.
5. Press the Exit and Leak Check buttons simultaneously. The display will change to:
Enter Cal Mode?
6. Press the Leak Check button to proceed with calibration or select the Exit button to
exit out of the calibration mode without any changes being made.
7. At this point the display will read:
Go To 0 Feet
Next
CHAPTER 4
14