7
Trim the transmitter
Devices are calibrated by the factory. Once installed, it is recommended to
perform a zero trim on gage 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.
Note
When performing a zero trim, ensure the equalization valve is open and all
wet legs are filled to the correct level.
CAUTION
It is not recommended to zero an absolute transmitter, Rosemount 2051HTA
model.
Procedure
Choose your trim procedure.
a) Analog zero trim – Sets the analog output to 4 mA.
b) Also referred to as a “rerange,” it sets the lower range value (LRV)
equal to the measured pressure.
c) The display and digital HART output remains unchanged.
d) Digital zero trim – Recalibrates the sensor zero.
e) The LRV is unaffected. The pressure value will be zero (on display and
HART output). 4 mA point may not be at zero.
f) This requires the factory calibrated zero pressure is within a range of
3% of the URV [0 ± 3% x URV].
Example
Example
URV = 250 inH
2
O Applied Zero Pressure = ± 0.03x 250 inH
2
O = ± 7.5 inH
2
O
(compared to factory settings) values outside this range will be rejected by
the transmitter
7.1 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.
February 2019
Quick Start Guide
Quick Start Guide
23
