5. MAINTENANCE, ADJUSTMENTS AND CALIBRATION
Page 131
© 2007 DH Instruments, a Fluke Company
Press
[SPECIAL]
,
<8Cal>
,
<1Q-RPT>
,
<2edit>
and write the new calibration date and
the new values of PA and PM for the Q-RPT and range calibrated. If this is an Axxx
Q-RPT used in absolute mode, edit the value of P
offset
to zero. If this is an Axxx Q-RPT and
the calibration was performed in gauge mode, turn absolute mode OFF so that it cannot be
used after the calibration.
Calculate as left data for the calibration, if desired, following:
as left reading = (non-corrected reading • new PM) + new PA
Perform additional verification pressure runs as desired.
5.3
ADJUSTMENT OF ON-BOARD BAROMETER
PURPOSE
To adjust the output of the on-board barometer (see Sections 1.2.2.3, 3.5.7.2, 5.9.1.5).
PRINCIPLE
The on-board barometer output can be adjusted using PA and PM values in the same manner as Q-
RPTs (see Section 5.2.1.1).
The on-board barometer is a low accuracy sensor used only for measuring changes in atmospheric
pressure over short periods of time (see Section 3.2.4). PPCH-G measurement uncertainty does not depend
on the measurement uncertainty of the on-board barometer unless it is used as a source of
P
std,0
for AutoZ in
absolute measurement mode (see Section 3.5.1).
OPERATION
To edit the values of PA and PM for the barometer, press
[SPECIAL]
,
<8cal>
,
<2barometer>
. Pressing
[ENT]
steps through displays of the calibration date
<YYYYMMDD>
and PA and PM. In
edit
mode, the
values can be edited. Pressing
[ENT]
after the last screen activates the edited values.
To view the current output of the on-board barometer, press [SPECIAL], <7Internal>, <2baro>.
5.4
ADJUSTMENT OF UTILITY SENSOR
PURPOSE
To adjust the output of the utility sensor, if present (see Section 1.2.2.2).
PRINCIPLE
PPCH-Gs that do not have a Q-RPT in the Internal, Hi (IH) position, have a utility sensor.
The utility sensor output can be adjusted using PA and PM values in the same manner as for the Q-RPTs
(see Section 5.2.1.1).
The utility sensor is not intended to serve as a pressure reference for low uncertainty, traceable
measurement. It is for indication, pressure control and system maintenance functions only. PPCH-G measurement
uncertainty when using Q-RPTs does not depend on the measurement uncertainty of the utility sensor.
