Aalborg PWE Digital - Manual (Page 64)

59
6.2 Flow Meter Span Calibration
Using Aalborg ® supplied calibration and maintenance software start Set Span
procedure by navigating to the Tools/Set Span/PulseCounts menu. The software
will display screen with current frequency and calculated Calibration Factor.
Using the installation flow regulator, adjust the flow rate to 100% of full scale
flow. Check the flow rate indicated against the flow calibrator. Once required flow
rate is established click Save button. The new Calibration Factor will be saved in
to the EEPROM table (index 61) and device linearization table (EEPROM indexes
62-83) will be initialized with default linear values.
Calibration Factor also can be adjusted using local LCD/KeyPad interface (see
Section 4.9.3).
6.3 Flow Meter Linearization Table Calibration
The PWE flow linearization table calibration involves building a table of the actual
flow values (EEPROM indexes 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82) and cor-
responding sensor readings (EEPROM indexes 63, 65, 67, 69, 71, 73, 75, 77, 79,
81, 83). Actual flow values are entered in normalized fraction format: 100.000 %
F.S. corresponds to 1.000000 flow value and 0.000 % F.S. corresponds to
0.000000 flow value. The valid range for flow values is from 0.000000 to 1.000000
(note: PWE will accept up to 6 digits after decimal point). Sensor readings are
entered in pulses and should always be in the range of 10 to 4000. There are 11
elements in the table so the data should be obtained at an increment of 10.0 % of
full scale (0.0, 10.0, 20.0, 30.0, 40.0, 50.0, 60.0, 70.0, 80.0, 90.0 and 100.0 %
F.S.).
Note: Your PWE Flow Meter was calibrated at the factory for the
specified fluid and full scale flow range (see device’s front label). There
is no need to adjust the Calibration Factor or Flow linearization table
unless linearity adjustment is needed, flow range has to be changed.
Any alteration of the Calibration Factor or flow linearization table will
VOID calibration warranty supplied with instrument.
,
Note: Described above procedure will reinitialize entire Linearization
table. If it is desirable to keep existing linearization table and only minor
adjustment of the calibration curve is required it is recommended
perform linearization table adjustment starting from 90% F.S.
(see Section 6.3).
,