54
Reference Manual
00809-0100-4108, Rev CA
Operation and maintenance
March 2017
Operation and maintenance
5.3 Recommended calibration tasks
5.3.1 Field installation tasks
1. Perform sensor zero/lower trim: Compensate for mounting pressure effects
a. Refer to Section 3: Rosemount 306 Manifold for manifold operation instructions to
properly drain/vent valves
2. Set/check basic configuration parameters
a. Output units
b. Range points
c. Output type
d. Damping Value
5.3.2 Bench calibration tasks
1. Perform optional 4–20 mA 1–5 Vdc output trim
2. Perform a sensor trim
a. Zero/lower trimpage 66 using line pressure effect correction. Reference Section 3:
Rosemount 306 Manifold for manifold drain/vent valve operation instructions.
b. Optional full scale trim. Sets the span of the device and requires accurate calibration
equipment.
c. Set/check basic configuration parameters.
5.4 Calibration overview
The Pressure Transmitter is an accurate instrument that is fully calibrated in the factory.
Field calibration is provided to the user to meet plant requirements or industry standards.
Complete calibration of the transmitter can be split into two halves: Sensor Calibration and
Analog Output Calibration.
Sensor calibration allows the user to adjust the pressure (digital value) reported by the
transmitter to be equal to a pressure standard. The sensor calibration can adjust the
pressure offset to correct for mounting conditions or line pressure effects. This correction is
recommended. The calibration of the pressure range (pressure span or gain correction)
requires accurate pressure standards (sources) to provide a full calibration.
Like the Sensor calibration, the analog output can be calibrated to match the user
measurement system. The Analog Output Trim (4–20 mA/ 1–5 V output trim) will calibrate
the loop at the 4 mA (1 V) and 20 mA (5 V) points.
The Sensor calibration and the analog output calibration combine to match the
transmitter’s measurement system to the plant standard.
Absolute pressure transmitters are calibrated at the factory. Trimming adjusts the position
of the factory characterization curve. It is possible to degrade performance of the
transmitter if any trim is done improperly or with inaccurate equipment.
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