ABB 266 MODBUS User Manual page 48

Validating transmitter measurement
The transmitter is factory calibrated to traceable standards. For most applications, validation of the device is preferred over a full
calibration. For applications that require calibration to the end user's standards refer to section 5.12, Calibrating.
Validating SP measurement system
This procedure can be used to validate the static pressure measurement system.
1. Verify the high and low pressure tap valve connections on the stream are closed to shut off the process flow (Figure 33,
item L and H).
2. Open the low and high side equalizer valves (items A and B).
3. Vent the high (+) and low (-) side of the manifold to atmosphere by opening the manifold vent valve (item C).
4. Verify the static pressure reading is equal to the barometric pressure.
5. Close the manifold vent valve (item C).
IMPORTANT NOTE: When validating the static pressure system, pressure must be applied to the high and
low side of the transmitter. Failure to do so could result in false indications of measurement and in extreme
cases could shift the differential measurement out of specification.
6. Attach the static pressure calibration tool to the high side manifold test port.
7. Apply the pressure corresponding to the requirements of the application.
8. The applied pressure will be visible on the device display.
9. Record the data necessary to satisfy the requirements of the application.
10. Continue with the validation until all the requirements have been met.
40 | 266 MODBUS® multivariable transmitter User manual 2105216 Rev. AB
4 Transmitter start up