PPC3™ OPERATION AND MAINTENANCE MANUAL
© 2002-2007 DH Instruments, a Fluke Company Page 42
After the last point in the sequence has
been completed, the display is:
AutoTest complete
1exit 2repeat 3data
Select <1exit> to go the MAIN run screen retaining the AutoRange that was
setup by QDUT.
Select <2repeat> to start the same test again at <Exercise DUT & [ENT]>.
Select <3data> to view the data collected in the QDUT AutoTest that was just
completed (see Section 3.4.5).
3.3.7 [HEAD]
PURPOSE
To cause a pressure fluid head correction to be added or subtracted to the pressure
measured by the PPC3 reference pressure transducer in order to predict the pressure at a
height other than the PPC3’s reference level.
PRINCIPLE
PPC3 measures gauge or absolute pressure at the height of the rear panel TEST(+) port.
Frequently, when performing a calibration or test, the device or system under test is at a
different height than the PPC3’s TEST(+) port. This difference in height, frequently called
head, can cause a significant difference between the pressure measured by the PPC3 at its
TEST port height and the pressure actually applied to the device under test which is at a
different height. In this case, it is useful to make a head correction to the pressure measured
by the PPC3 in order to predict the pressure actually applied at a different height.
PPC3 can calculate head pressures for nitrogen, helium and air as the test gas over its working
pressure range. The HEAD function allows the height difference to be specified and causes
the resulting head pressure to be added to the pressure measured at the TEST port.
The [HEAD] function key is used to specify the height difference between the PPC3 TEST
port and another height. Entering a height of zero turns the function off. The height units and
the test gas are specified by pressing [SPECIAL], <3Head> (see Section 3.5.3).
Use of the HEAD function to assure in tolerance measurements is most important in low
absolute pressure ranges. Specifying the head height within ± 3 in. (7.5 cm) is adequate
to assure that, even in the worst case, the uncertainty on the head correction will be
insignificant relative to the tolerance on the measurement.
OPERATION
To access the HEAD function, press the [HEAD] function key. The display is:
1. Entry field for head height.
2. Test gas currently specified for the head correction.
Edit head height:
+ 25 cm N2
Edit the head height to the desired value. Press [ENT] to return to the MAIN RUN screen
with the new head correction active. Press [ESC] to return with no changes.
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