Rosemount 3051S Electronic Remote Sensors - Emerson Process ...

Reference Manual
00809-0100-4804, Rev AA
January 2011
Figure 3-3. Scaled Variable -
Level Example
Specific Gravity
= 0.94
4.5 feet
1.5 feet
Rosemount 3051S ERS System
Scaled Variable Configuration
1. Scaled Units FEET METER
2. DP 1 (Minimum DP) 0 (in. H 2 0) 0 (mmH 2 0)
3. Scaled 1 (Level at Min. DP) 1.5 (feet) 0.46 (meters)
4. DP 2 (DP at Max Level) 50.76 (in. H 20) 1289 (mmH 20)
5. Scaled 2 (Max Level) 6.0 (feet) 1.83 (meters)
6. Primary Variable Scaled Variable
LRV (4 mA) 1.5 (feet) 0.46 (meters)
URV (20 mA) 6.0 (feet) 1.83 (meters)
Configuring Scaled Variable to Calculate Mass or Volume
Fast Keys 2, 2, 3, 5, 1
To derive a mass or volume calculation from a DP measurement, more than
two Scaled Variable points may be required depending on the tank shape and
geometry. ERS supports three different methods for configuring Scaled
Variable for mass or volume applications:
• Direct: manually configure Scaled Variable using anywhere from two to
20 points.
• Tank Formulas: Scaled Variable will automatically be configured by
inputting the tank shape, tank geometry, and specific gravity of the
process.
• Strapping Table: Scaled Variable will automatically be configured by
inputting a traditional “Level vs. Volume” strapping table.
Direct Method
The steps required to configure Scaled Variable for a Mass or Volume
application using the Direct Method are highlighted below:
1. Enter in a text string (up to 5 characters: A-Z, -, %, /, *, and “space”) to
define the unit of measure for the scaled output. Examples include
GALNS, POUND, or LITER.
2. Define the number of Scaled Variable points that will be configured (valid
range = 2 – 20).
3. Enter the first DP value (in engineering units) and the corresponding
Scaled Variable value.
4. Repeat Step #3 for the number of Scaled Variable points defined in Step
#2.
3-9