ABB XSeries G4 6200, Руководство пользователя, Страница: 121 / 168

2104349 rev. AD Page 4
–23
8) Enter a pressure marker for differential pressure
“0.0”. Click the OK button.
9) Close the high side equalizer valve, and verify that the low side is vented to
atmosphere.
10) Connect Calibration Standard to the calibration test port.
11) Pressure to the next preferred verification pressure.
12) When the current reading stabilizes, enter the pressure value from the
calibration source. Click the OK button.
13) Repeat steps 11 through 12 for each pressure check value.
14) When all the differential pressure markers have been set, determine if
calibration is required. If no calibration is required, return the manifold to
service before exiting Calibration mode.
For additional information regarding Differential Pressure
Calibration Checks, see the PCCU32 Help Files.
4.13.5 Calibrating static pressure (SP)
A three or five point pressure method is used to calibrate the G4 EX static
pressure cell. These different pressures are applied to the cell from a known,
traceable source. The resultant pressure values are entered into the G4 EX using
PCCU32 software.
When performing the following procedures, wait for the G4 EX display to stabilize.
If the G4 EX is not in Calibration mode, the display will not necessarily match
applied cell pressures.
The G4 EX uses an absolute static pressure (SP) cell.
Absolute pressure measures the pressure referenced to a
vacuum or sealed chamber. This is different than a gauge
cell which measures the pressure referenced to the
atmosphere.
Since the static pressure cell is an absolute device, it always
measures the true pressure relative to a vacuum or sealed
chamber. As such, when vented, it measures true
barometric pressure.
For other points of calibration, add the reading of PSI and
barometric pressure to arrive at PSIA. Upon completion,
enter this reading.
4.13.5.1
Absolute versus gauge
It is recommended that the initial calibration point be at vented conditions. When
this is done, the barometric reading (in PSI) should be used as the initial point.
When operating in PCCU32’s Absolute mode, other points of calibration are
arrived at by adding the PSI reading and the barometric pressure to arrive at
PSIA. Once this has happened, enter this reading.
When operating in PCCU32’s Gauge mode, readings may be entered in as read,
and then a barometric pressure reading is entered.