PRESTON PRESSURE PS-500 User And Maintenance Manual page 17

record to see if the sensors are drifting with age. A good place to keep the calibration
correction values is in this manual.
9. After pressing the Units button, the display will change to display Go to 10000 feet.
10. Repeat the procedure in step 8 at each requested altitude: 10000, 20000, 30000 and
40000, feet.
11. After entering the calibration value of the highest altitude, pressing the Units button
will change the calibration to the VSI calibration mode. Select a vertical descent speed
(5,000 feet is suggested) on the calibration test equipment and activate it. The display will
indicate the calculated VSI value. Adjust if needed by pressing the Exit or Leak Check
buttons. When finished, press the Units button. The VSI calibration value will be saved.
12. After the VSI calibration has been entered, the display will briefly read
Calibration
Saved
and then re-start in the altitude mode. There is no need to re-cycle power.
13. Bring the PS-500 box back down to ground level pressure, then test each calibration
point as specified in the chart. Enter the corrected value at each point. (The correction
chart may be photocopied, cut out, and fixed to the test box for handy reference.)
Maximum allowable error at any altitude is 70 feet. (Generally, a maximum error of less
than 20 feet should be expected.)
PS-500 S/N
FOR TEST DISPLAY FOR TEST
ALTITUDE ALTITUDE ALTITUDE
- 1000
-500 11000
0
500
1000 16000
1500 18000
2000 20000
3000 22000
4000
6000
8000 35000
Calibrated by: ___________ Date: __________
Next Calibration Due Date: ________________
DISPLAY
ALTITUDE
10000
12000
14000
25000
30000
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