Emerson Rosemount 3051S MultiVariable Reference Manual page 113

Reference Manual
00809-0100-4803
Zero trim and lower sensor trim
The type of static pressure sensor equipped in the transmitter can be determined by
referring to the Static Pressure Sensor Type heading. This determines whether a zero trim
(gage sensor) or lower sensor trim (absolute sensor) required to correct for mounting
position effects.
To perform a zero trim on a gage static pressure sensor, select the Zero Trim button under
the Static Pressure Sensor Trim heading and follow the on-screen prompts. The
transmitter must be within five percent or less of the maximum span of true zero (zero-
based) in order to calibrate with zero trim function.
To correct for mounting position effects on transmitters equipped with an absolute static
pressure sensor, perform a lower sensor trim. This is accomplished by selecting the Lower
Sensor Trim button and following the on-screen prompts. The lower sensor trim function
provides an offset correction similar to the zero trim function, but it does not require a
zero-based input.
Static pressure full sensor trim
To perform a Static Pressure Full Sensor Trim, perform the following procedure:
Procedure
1. Select the Lower Sensor Trim button and follow the on-screen prompts.
2. Select the Upper Sensor Trim button and follow the on-screen prompts.
Example
Note
It is possible to degrade the performance of the transmitter if the full sensor trim is done
improperly or with inaccurate calibration equipment. Use a pressure input source that is at
least three times more accurate than the transmitter and allow the pressure input to
stabilize for ten seconds before entering any values.
Recall factory trim
The Recall Factory Trim button will restore the transmitter to the original factory
characterization curve. The Recall Factory Trim button can be useful for recovering from
an inadvertent zero trim or inaccurate pressure source.
When the recall factory trim function is used, the transmitter's upper and lower trim
values are set to the values configured at the factory. If custom trim values were specified
when the transmitter was ordered, the device will recall those values. If custom trim values
were not specified, the device will recall the upper and lower sensor limits.
Emerson.com/Rosemount
Operation and Maintenance
October 2018
113