Emerson Rosemount 2051 Reference Manual page 27

Reference Manual
00809-0100-4107
Figure 2-13: Configuring Alarm and Saturation with LOI
2.8.2 Configuring scaled variable
The Scaled Variable configuration allows the user to create a relationship/conversion
between the pressure units and user-defined/custom units. There are two use cases for
Scaled Variable. The first use case is to allow custom units to be displayed on the
transmitter's LCD/LOI display. The second use case is to allow custom units to drive the
transmitter's 4–20 mA (1–5 Vdc) output.
If the user desires custom units to drive the 4–20 mA (1–5 Vdc) output, Scaled Variable
must be re-mapped as the primary variable. Refer to
The Scaled Variable configuration defines the following items:
• Scaled Variable units - custom units to be displayed.
• Scaled data options - defines the transfer function for the application (linear and square
root)
• Pressure value position 1 - lower known value point with consideration of linear offset.
• Scaled Variable value position 1 - custom unit equivalent to the lower known value
point.
• Pressure value position 2 - upper known value point
• Scaled Variable value position 2 - custom unit equivalent to the upper known value
point
• Linear offset - the value required to zero out pressures effecting the desired pressure
reading.
• Low flow cutoff - point at which output is driven to zero to prevent problems caused by
process noise. It is highly recommended to use the low flow cutoff function in order to
have a stable output and avoid problems due to process noise at a low flow or no flow
condition. A low flow cutoff value that is practical for the flow element in the
application should be entered.
Configuring scaled variable using a Field Communicator
From the HOME screen, enter the Fast Key sequence.
Device Dashboard Fast Keys
Reference Manual
VIEW CONFIG
ZERO TRIM
UNITS
RERANGE
LOOP TEST
DISPLAY
EXTENDED MENU
EXIT MENU
EXTENDED MENU
CALIBRAT
DAMPING
TRANSFER FUNCT
SCALED VARIAB
ASSIGN PV
TAG
ALARM SAT VALUES
PASSWORD
SIMULATE
HART REV
BACK TO MENU
EXIT MENU
Re-mapping device
2, 1, 4, 7
Configuration
September 2020
ALARM SAT VALUES
ROSEMOUNT VALUES
NAMUR VALUES
OTHER VALUES
BACK TO MENU
EXIT MENU
variables.
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