ABB XSeries G4 6200, Руководство пользователя, Страница: 123 / 168

2104349 rev. AD Page 4
–25
21) Upon completion of the SP calibration, new calibration markers should be
set.
22) Return the manifold to service before exiting Calibration mode.
4.13.6 Calibrating differential pressure (DP)
A three or five point pressure method is used to calibrate the G4 EX differential
pressure cell. These different pressures are applied to the cell from a known,
traceable source. The resultant pressure values are then entered in the G4 EX
using PCCU32 software.
During factory calibration, any differential pressure (DP) shift due to static
pressure effect is corrected. This is not user configurable and will not be modified
due to field or user calibration. This ensures that the readings received in the field
are accurate. The user may not change the factory set shift. If readings appear
incorrect, the user may need to check for leaks and then recalibrate the DP.
When calibrating, wait for the readings to stabilize before entering the new values.
4.13.6.1
Step-by-step instructions
1) Enter the Calibration men
u’s Calibration screen. This places the G4 EX in
HOLD.
2) Select DP from the Calibration drop-down box to the left of the Pressure
Marker table. Select 3 or 5 Point Calibration.
3) Set the Transducer DP Pressure Range in the Calibration window before
proceeding. This should match the range reading from the tag or label
attached to the transducer. Target values based on the selected range will
display in the Calibration table.
4) Verify that the vent valve is closed (see Figure 4
–12).
5) Open both the high and low equalizer valves.
6) Close both the downstream and upstream tap valves.
7) Open the atmospheric vent valve.
8) Click on the Low Cal Point button. Verify the current reading is continuously
updated.
9) When the current reading stabilizes, click the OK button; otherwise, enter a
different value, and click the OK button.
10) When the previous reading was accepted, notice that the 100% Cal Point
button becomes activated. To select, press Enter.
11) Connect the Calibration Standard to the calibration test port.
12) Close the high side equalizer valve, and verify that the low side is vented to
atmosphere.
13) Pressure to 100% of the transducer range (100% of target value).
14) When the current reading stabilizes, accept the target value already
showing in the window; otherwise, enter the pressure value from the
calibration source. Click the OK button.
15) Again, notice that the next Cal Point is activated. To select, press Enter.
16) Pressure the transducer to the next target value as shown in the Calibration
window.