13
The letter P indicates that the sensor being calibrated in this step is the Pitot sensor.
(Where Altitude is the sensed altitude in feet, and xxx is the current calibration value.)
Write down the calibration value so it can be re-set if needed!
The word “In” is displayed above the Units button. Press the Units button when ready to
input the selected correction value.
6. Go to a pressure that corresponds to the selected calibration point (referenced from
29.92 inHg), as read from a pressure standard. When the altitude is stable for
approximately 30 seconds, note the altitude displayed on the PS-425 display in
calibration mode.
If the displayed altitude is lower than the standard, press the Exit button as needed to
incrementally raise the altitude to be equivalent to the standard.
If the displayed altitude is higher than the standard, press the Leak Check button as
needed to incrementally lower the altitude to be equivalent to the standard.
As the altitude is adjusted, note that the displayed correction factor also changes, and the
change is in increments smaller than the altitude. Use this to fine-tune the altitude as
close as you can to the standard.
When the PS-425 altitude matches the standard as close as possible, wait another 30
seconds to ensure that the internal mathematical filtering corrections have been done. If
satisfied with the results, press the Units button to Input the selected correction, and the
display will automatically proceed to the next calibration level.
7. Repeat the procedure in step 7 at each requested altitude: 10000, 20000, 30000 and
40000 feet as needed.
8. After the last calibration point has been entered, the display will briefly read
“Storing” and then re-start. There is no need to re-cycle power.
9. After bringing the PS-425 back down to ground level pressure, wait at least 1 minute
for settling. Then, test each calibration point as specified in the chart on page 14. Enter
the corrected value at each point. (The correction chart may be photocopied, cut out, and
fixed to the test box for handy reference.)
Helpful Notes: When the display is indicating “Go To XX Feet”, pressing the Light
button will cycle through the various calibration points of 0, 10,000, 20,000 feet, etc.
After 40,000 feet it will exit the calibration mode. This is handy for use in those cases
when only one range is in need of calibration. Note, however, that the PS-425 unit’s
pressure must be within less than 2,500 feet of the selected range in order to save the new
value. This eliminates accidentally saving a value when in an incorrect pressure range.
To Next Page
Loading...