5-17
Figure 5-6. Flowmeter Data Flow with
Calibration Options
Deciding Which Trim Procedure to Use
To decide which trim procedure to use, you must first determine
whether the analog-to-digital section or the digital-to-analog section of
the flowmeter electronics is in need of calibration. To do so, refer to
Figure 5-6 and perform the following procedure:
1. Connect a pressure source, a HART communicator, and a digital
readout device to the flowmeter.
2. Establish communication between the flowmeter
and the communicator.
3. Apply pressure equal to the upper range point pressure
(100 in H
2
0, for example).
4. Compare the applied pressure to the Secondary Variable (Press)
line on the Communicator Process Variables Menu. If the Press
reading on the communicator does not match the applied pressure,
and you
are confident that your test equipment is accurate, perform a
sensor trim.
5. Compare the Analog Output (AO) line on the communicator
on-line menu to the digital readout device. If the AO reading on the
communicator does not match the digital readout device, and you
are confident that your test equipment is accurate, perform an
output trim.
HART
Communications
Microprocessor
Digital PV
Digital-to-Analog
Signal Conversion
Analog-to-Digital
Signal Conversion
Flowmeter Electronics Module
Analog Output
100 in H
2
O
(Flowmeter Ranged 0 to 100 in H
2
O)
ProPlate: FT-4001
Process Variables
1Flow Press
2% rnge100.00
3AO20.00 mA
4Press0.00 inH2O
5Snsr Temp23.0°C
Output Device
20.00 mA
Input Device
NOTES
1)Value on PV line should equal
the input pressure
2)Value on AO line should equal the
output device reading
Sensor
Signal
Input
Pressure
Sensor
To Next Page
Loading...
