TB 9-4920-459-24
b. Adjustments
NOTE
If adjustment does not correct TI accuracy, restoration of corrupt data files in
TI may be required. Restoration requires the use of Special Type Test
is at Secondary Reference Level.
The alignment procedures may be
accomplished at Transfer Level with TM 43-4920-910-40, paragraph 3-53, by
transferring the STTE via temporary hand receipt to Transfer Level facility
as applicable to restore data files to TI.
(1) Connect pneumatic pressure standard 17 PSIA inlet port to the Pt outlet port of
the TI.
(2) Tightly cap closed the Ps outlet port of the TI.
(3) Configure the pneumatic pressure standard to read psi absolute on the 17 psia channel.
(4) Remove calibration label that covers the calibration enable screw on the TI and
unscrew the calibration enable screw counterclockwise until it is free to rotate.
(5) Press CLEAR/QUIT key and select CALIBRATION MODE by pressing F1
and F4 keys simultaneously.
(6) When the last calibration date and the current calibration date are displayed,
press the ENTER key, and accept the current calibration date, or re-enter the date if incorrect.
(7) The main calibration menu will be displayed.
Press F2 key to select
CALIBRATION CHECK.
(8) Press F1 to select INTERNAL.
(9) Press F4 to select Ps and Pt (abs).
(10) Press F2 to select RATE and enter 10 psi/min.
(11) Press F1 to select AIM and enter 5 psi. Wait for aim to be achieved then
wait 1 minute.
(12) Press F3 to select OFF to select MEASURE MODE, wait for 5 minutes.
(13) Note the Ps pressure displayed on the TI then note the Ps pressure again 1 minute
later. Check that the difference between the readings (leak rate) is less than 0.015 psi. If the
leak rate is greater than 0.015 psi/min, repeat the 5 minute wait and retest. If still greater
than 0.015 psi, then check the integrity of the pneumatic connections. Leak test the
pneumatic pressure standard and leak test the TI.
(14) With the leak rate less than 0.015 psi/min, press F3 to select ON to regain
control, then press F1 then enter an aim of 14.5 psi and wait for it to be achieved.
(15) Press CLEAR/QUIT key repeatedly to return to the main calibration menu.
Press F1 key to select MAIN CALIBRATION.
(16) Press F1 key to select INTERNAL PRESSURE SOURCE.
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