Trimming The Pressure Signal - Emerson Rosemount 2051 Reference Manual

Reference Manual
00809-0100-4107
Complete the upper sensor trim procedure as described in
However, enter the calculated correct upper sensor trim value of 1517.1 inH
communication device.
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Trimming the pressure signal

5.6 Trimming the pressure signal
5.6.1 Sensor trim overview
A sensor trim corrects the pressure offset and pressure range to match a pressure
standard.
The upper sensor trim corrects the pressure range, and the lower sensor trim (zero trim)
corrects the pressure offset. An accurate pressure standard is required for full calibration.
You can perform a zero trim if the process is vented or the high and low side pressure are
equal (for differential pressure transmitters).
Zero trim is a single-point offset adjustment. It is useful for compensating for mounting
position effects and is most effective when performed with the transmitter installed in its
final mounting position. Since this correction maintains the slope of the characterization
curve, it should not be used in place of a sensor trim over the full sensor range.
When performing a zero trim, ensure the equalizing valve is open and all wet legs are filled
to the correct levels. Apply line pressure to the transmitter during a zero trim to eliminate
line pressure errors.
Note
Do not perform a zero trim on Rosemount 2051T Absolute Pressure Transmitters. Zero
trim is zero based, and absolute pressure transmitters reference absolute zero. To correct
mounting position effects on an absolute pressure transmitter, perform a low trim within
the sensor trim function. The low trim function provides an offset correction similar to the
zero trim function, but it does not require zero-based input.
Upper and lower sensor trim is a two-point sensor calibration where two end-point
pressures are applied and all output is linearized between them; these trims require an
accurate pressure source. Always adjust the low trim value first to establish the correct
offset. Adjustment of the high trim value provides a slope correction to the characterization
curve based on the low trim value. The trim values help optimize performance over a
specific measurement range.
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Trimming the pressure signal.
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