Emerson Rosemount 248 Reference Manual page 19

Reference Manual
00809-0100-4248
2.4.4 Fast Key sequence
This section lists the Fast Key sequences for common transmitter functions.
Note
The Fast Key sequences assume that Device Revision 01, DD Revision 01 or greater is being
used.
Table 2-2: Fast Key Sequence
Function
Device Information
Lower Range Value
PV Range Values
Sensor Configuration
Sensor Trim (Calibration)
Upper Range Value
Wireless Network
2.4.5 Calibration
Calibrating the transmitter increases the measurement precision by allowing corrections to
be made to the factory-stored characterization curve. It does this by digitally altering the
transmitter's interpretation of the sensor input.
To understand calibration, it is necessary to understand that smart transmitters operate
differently from analog transmitters. An important difference is that smart transmitters are
factory-characterized, meaning that they are shipped with a standard sensor curve stored
in the transmitter firmware. In operation, the transmitter uses this information to produce
a process variable output, in engineering units, dependent on the sensor input.
Note
Calibration of the transmitter may include Sensor Input Trim: Digitally alter the
transmitter's interpretation of the input signal.
Trim the transmitter
The Sensor Input Trim function may be used when performing calibrations.
Sensor calibration
Fast Keys: 3, 5, 2
If the transmitter's digital value for the primary variable does not match the plant's
standard calibration equipment, then Emerson recommends performing a sensor trim. The
sensor trim function calibrates the sensor to the transmitter in temperature units or raw
units. Unless your site-standard input source is NIST-traceable, the trim functions will not
maintain the NIST-traceability of the system.
The Sensor Input Trim command allows the transmitter's interpretation of the input signal
to be digitally altered. The sensor reference command trims, in engineering (°F, °C, °R, K)
or raw (Ω, mV) units, the combined sensor and transmitter system to a site standard using
Rosemount 248
Key sequence Menu items
1, 7 Identification, Revisions, Radio, Security
2, 2, 2, 6, 3, 2 Set the temperature for the 0% point to configure
the Percent of Range.
2, 2, 3 Primary Variable Lower Range Value (PV LRV),
Primary Variable Upper Range Value (PV URV), LSL,
USL
2, 1, 1 Configure Sensor Type and Units, View Current
Sensor Configuration
2, 1, 4 Lower Sensor Trim and Upper Sensor Trim
2, 2, 2, 6, 3, 1 Set the temperature for the 100% point to
configure the Percent of Range.
2, 1, 2 N/A
Configuration
April 2024
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