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Overview
The Lower Range Value (LRV) and Upper Range Value (URV) are used to scale the mA output,
that is, to define the relationship between mA Output Process Variable and the mA output
level.
Note
For transmitter software v5.0 and later, if you change LRV and URV from the factory default values,
and you later change mA Output Process Variable, LRV and URV will not reset to the default values. For
example, if you set mA Output Process Variable to Mass Flow Rate and change the LRV and URV, then you
set mA Output Process Variable to Density, and finally you change mA Output Process Variable back to Mass
Flow Rate, LRV and URV for Mass Flow Rate reset to the values that you configured. In earlier versions of
the transmitter software, LRV and URV reset to the factory default values.
Procedure
Set LRV and URV as desired.
• LRV is the value of mA Output Process Variable represented by an output of 4 mA. The
default value for LRV depends on the setting of mA Output Process Variable. Enter LRV in
the measurement units that are configured for mA Output Process Variable.
• URV is the value of mA Output Process Variable represented by an output of 20 mA. The
default value for URV depends on the setting of mA Output Process Variable. Enter URV in
the measurement units that are configured for mA Output Process Variable.
Tips
For best performance:
• Set LRV ≥ LSL (lower sensor limit).
• Set URV ≤ USL (upper sensor limit).
• Set these values so that the difference between URV and LRV is ≥ Min Span (minimum span).
Defining URV and LRV within the recommended values for Min Span, LSL, and USL ensures that the
resolution of the mA output signal is within range of the bit precision of the D/A converter.
Note
You can set URV below LRV. For example, you can set URV to 50 and LRV to 100.
The mA output uses a range of 4–20 mA to represent mA Output Process Variable. Between
LRV and URV, the mA output is linear with the process variable. If the process variable
drops below LRV or rises above URV, the transmitter posts an output saturation alarm.
Default values for Lower Range Value (LRV) and Upper Range Value
(URV)
Each option for mA Output Process Variable has its own LRV and URV. If you change the
configuration of mA Output Process Variable, the corresponding LRV and URV are loaded and
used.
Integrate the meter with the control system
Configuration and Use Manual 83