6 Trim the transmitter
Devices are calibrated by the factory. Once installed, it is recommended to
perform a zero trim on gage and absolute pressure transmitters to eliminate
error due to mounting position or static pressure effects. A zero trim can be
performed using either a Field Communicator or configuration buttons.
For instructions using AMS Device Manager, see the Rosemount 2088
Reference Manual.
CAUTION
It is not recommended to zero an absolute transmitter.
Procedure
Select trim procedure.
a) Analog zero trim – sets the analog output to 4 mA.
Also referred to as a “rerange,” it sets the Lower Range Value(LRV)
equal to the measured pressure. The display and digital HART output
remains unchanged.
b) Digital zero trim – recalibrates the sensor to zero.
The LRV is unaffected. The pressure value will be zero (on display and
HART output). 4 mA point may not be at zero. This requires that the
factory calibrated zero pressure is within a range of three percent of
the URV [0 ± 3% x URV].
Example
URV = 250 inH
2
O
Applied zero pressure = 0.03 x 250 inH
2
O = 7.5 inH
2
O (compared to factory
settings) values outside this range will be rejected by the transmitter
6.1
Trimming with a Field Communicator
Procedure
1. Connect the Field Communicator, see Connect the wiring and power
up for instructions.
2. Follow the HART menu to perform the desired zero trim.
Table 6-1: Zero Trim Fast Keys
Analog zero (Set 4 mA) Digital zero
Fast Key sequence 3, 4, 2 3, 4, 1, 3
Quick Start Guide March 2022
20 Emerson.com/Rosemount
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