DH Instruments PPC3 - Power-Up and Verification; Switch Power on; Check Pressure Measurement Operation; Checking Absolute Mode Pressure Measurement

2. INSTALLATION
Page 13 © 2002-2007 DH Instruments, a Fluke Company
2.4 POWER-UP AND VERIFICATION
2.4.1 SWITCH POWER ON
Actuate the power switch on the PPC3 rear panel. Observe the front panel display as PPC3
initializes, error checks and goes to the MAIN RUN screen (see Section 3.1.1).
PPC3 power-up condition is Internal, Hi Q-RPT or utility sensor active, VENT ON unless the
pressure measured by the Hi Q-RPT is more than 20 kPa (3 psi) away from standard
atmospheric pressure.
If the PPC3 fails to reach the MAIN RUN screen, service is required. Record the sequence
of operations and displays observed.
2.4.2 CHECK PRESSURE MEASUREMENT OPERATION
2.4.2.1 CHECKING ABSOLUTE MODE PRESSURE MEASUREMENT
If the PPC3 has an Axxx (absolute) Q-RPT or a utility sensor (IuH), check that it
operates properly in absolute mode.
If the PPC3 is not vented (VENT LED OFF), press the [VENT] direct pressure
control key to vent the PPC3 (VENT LED ON) (see Section 3.1.3).
Using the [RANGE] function key to change ranges if necessary and select the
Axxx (absolute) Q-RPT DF range (see Section 3.3.1). Press the [MODE]
function key and select <absolute> mode (see Section 3.3.3). Use [UNIT] to
change the pressure unit if desired (see Section 3.3.2).
Observe the current value of atmospheric pressure. Check that the value agrees
with the local value of atmospheric pressure. Repeat this process for all the
Axxx (absolute) Q-RPTs and or the utility sensor in the PPC3 system. Check
that the values of atmospheric pressure measured by the different devices agree
with each other within PPC3 or RPM4 measurement tolerances as applicable
(see Section 1.2.2.1, 1.2.2.2). If they do not agree within tolerances, the PPC3
or RPM4 Q-RPT may need calibration or repair.
2.4.2.2 CHECKING GAUGE MODE PRESSURE MEASUREMENT
If the PPC3 is not vented, press the [VENT] direct pressure control key to vent it
(see Section 3.1.3).
Press the [MODE] function key and select <gauge> mode. Change the
pressure unit if desired (see Section 3.3.3).
Observe that, within ten seconds, zero is indicated. It is normal for PPC3 to indicate
a value other than zero for up to ten seconds when first entering gauge mode.
Using the [RANGE] function key to change ranges, observe that zero is
indicated for each Q-RPT within 10 seconds. It is normal for PPC3 to indicate a
value other than zero when vented when gauge mode is first entered or ranges
are changed. After about ten seconds, the VENT LED should flash and zero
should be indicated. If this does not occur, check that the AUTOZERO function
is ON (see Section 3.5.1). If AUTOZERO is ON and the displayed pressure will not
zero when vented in gauge or bi-directional gauge measurement mode, PPC3 may
need repair.