DH Instruments PPC4, Operation And Maintenance Manual

Page: 197 / 228

7. MAINTENANCE, ADJUSTMENTS AND CALIBRATION
Page 185 © 2009 DH Instruments, a Fluke Company
7.2.1.2 As Received and As Left Data
Frequently, calibration procedures require that as received and as left data be
reported. The necessary information to report as received and as left data on the
calibration of PPC4 Q-RPTs can be obtained in several ways.
When the PPC4 CalTool calibration assistance software is used, as received data
is displayed while running the calibration and is automatically recorded and
provided if desired. As left data is also calculated and presented.
At any time, a) reference pressures applied, b) associated transducer readings,
c) PA and PM and P
offset
values can be used to calculate as received and as left values.
For example, backing out PA and PM on the as left data yields the transducer
readings with PA = 0 and PM = 1. Then applying the as received PA and PM and
P
offset
values to the readings calculates as received readings
(the readings that the transducer would have made with the old PA, PM and P
offset
).
•
It is recommended that “as received” values of PA, PM and
P
offset
(for absolute mode calibrations if if AutoZero is used
in normal operation) be recorded for each Q-RPT prior to
running the calibration.
7.2.1.2.1 Basic Interface
The current PA and PM and absolute mode Poffset can be viewed by using
<Spec>, <Cal>, <Hi RPT/Lo RPT/Barometer>, <View> from the Main Menu.
The current value of gauge mode P
offset
can be viewed by using <Spec>,
<AutoZ>, <View> from the Main Menu.
7.2.1.2.2 Advanced Interface
The current PA, PM and Poffset values can be viewed by using [Settings],
<More >>>, <Calibration> . From this screen either the Hi RPT, Lo RPT or
Barometer may be viewed.
For both Hi and Lo RPT, using <Calibration> displays Cal Date, PA and PM. For
Hi and Lo RPT, using <AutoZ> diaplays the values for Gauge Poffset and, if the
Q-RPT is absolute, Absolute Poffset as well.
Using Barometer shows the Barometer screen, displaying Cal Date, PA , PM
and the current Barometer reading.
Note
If the security level is set to Low or High viewing the calibration
coefficients is allowed but no changes are accepted. A warning
is displayed when entering and exiting secure screens.
7.2.2 Equipment Required
Note
The recommended calibration standards for PPC4 Q-RPTs are DHI PG7000
gas operated piston gauges (PG7201, PG7202, PG7601). Contact DHI for
additional information.
Gas operated piston gauge (deadweight tester) , with the following characteristics:
•
Measurement uncertainty of ± 0.0025 % of reading for Standard or Full Scale
Standard Class Q-RPTs or ± 0.002 % of reading for Premium Class Q-RPTs
. A