ABB XSeriesG4 User Manual page 126

— PCCU32 version 7.05.5 or later
— Deadweight tester or equivalent calibration standard
— Test Gauge capable of dual range measurement (PSIG and Inches)
— Barometer or another means which can determine barometric pressure
— Nitrogen or compressed air source
IMPORTANT NOTE: If a method other than the 'compressed nitrogen/deadweight tester' method is used to
calibrate static pressure cell, the user must ensure that the prescribed flange tap valves are blocked to prevent
false differential pressure from being applied to DP cell. Also ensure that both high and low sides are pressured
up during SP calibration.
6.13.2 Hold Mode
When calibrating the XIMV or setting up a fixed temperature, PCCU will instruct the flow computer to ignore live values for the
flow calculations for the period of time the flow computer is being calibrated. This prevents real time flow calculations from being
affected during the calibration. During this time the flow computer uses SP, DP and temperature captured at the time calibration
mode was entered. (This is called the Hold mode.)
To exit the Hold mode:
Exit calibration mode.
Disconnect PCCU cable at the local connector.
IMPORTANT NOTE: Totalflow recommends performing a five point check before and after calibration. During
normal operation, either cell could be knocked out of calibration (typically due to a slug of liquid). WinCCU, the
host software, is capable of recalculating the volume based on the differences between the previous five point
check and the current five point check.
After a secure audit trail is archived, WinCCU recalculates the flow volumes based on the previous and current
markers, this allows more accurate results of the flow volume.
6.13.3 Static Pressure (SP) Calibration Checks
G4
The XFC allows for checking the static pressure calibration and log the pressure marker check points. The check should be
performed prior to and directly following the calibration.
During normal operation the display provides continuous SP readouts. However during calibration flow computer is placed in a
temporary hold mode.
A minimum of three SP markers should be set. The user may enter as many SP pressure markers as desired. Recording too
many markers could cause the flow computer to overwrite existing older events. Only the last five checks are used by the
WINCCU editor for calibration adjustment. Enter a 0%, 25%, 50%, 75% and 100% value.
Caution- Equipment damage. During this procedure, the user will pressure both sides of the cell by closing
!
both the high and low side orifice valves, open the vent to atmosphere, then closing the atmosphere vent and
opening both high and low bypass valves.
The resulting comparison pressure must not be greater than the static pressure cell's maximum pressure, or
damage may occur.
Equipment needed:
-Calibration standard
To perform Static Pressure (SP) calibration checks:
Connect the PC running PCCU32 to the flow computer with either an MMI cable (RS-232), a USB cable or an
Ethernet cable.
127 XFC G4 2103335 Rev AB