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Reference Manual
00809-0100-4102, Rev AA
Section 5: Operation and Maintenance
May 2013
Operation and maintenance
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 that the equalizing valve is open and all wet legs are filled
to the correct levels. Line pressure should be applied to the transmitter during a zero trim to
eliminate line pressure errors. Refer to “Manifold operation” on page 50.
Note
Do not perform a zero trim on 2051 Wireless absolute pressure transmitters. Zero trim is zero
based, and absolute pressure transmitters reference absolute zero. To correct mounting
position effects on a 2051 Wireless 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.
Sensor trim is a two-point sensor calibration where two end-point pressures are applied, and all
output is linearized between them. 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 allow you to optimize performance over your
specified measuring range at the calibration temperature.
During a trim operation, the 2051 Wireless is placed in high power refresh mode, which
provides frequent pressure measurement updates and allows the configured damping to take
effect. This behavior allows for more accurate calibration of the device. When the device is in
high power refresh mode, the battery power supply will be depleted more rapidly.
Figure 5-2. Sensor Trim example
A. Before Trim
B. After Trim
5.4.2 Sensor Trim
When performing a Sensor Trim, both the upper and lower limits can be trimmed. If both upper
and lower trims are to be performed, the lower trim must be done prior to the upper trim.
A.
B.
B.
A.