Emerson Rosemount 3051S MultiVariable - Page 61

Note
For Analog calibration, see Analog calibration.
Figure 2-40: Variables - Analog Output Tab
Procedure
1. Select the Primary Variable under the Analog Output Setup heading. The Upper
Range Value and Lower Range Value may also be edited under this heading.
2. Verify the Upper Sensor Limit and Lower Sensor Limit and minimum span under the
Primary Variable Sensor Limits heading.
Transfer function (direct process variable output feature
board only)
The Rosemount 3051SMV with direct process variable output feature board has two
analog output settings: Linear and Square Root. Activate the square root output option to
make analog output proportional to flow. As input approaches zero, the Rosemount
3051SMV automatically switches to linear output in order to ensure a smooth, stable
output near zero (see Figure 2-41).
From 0 to 0.6 percent of the ranged pressure input, the slope of the curve is unity (y = x).
This allows accurate calibration near zero. Greater slopes would cause large changes in
output (for small changes at input). From 0.6 to 0.8 percent, curve slope equals 41.72 (y =
41.72x) to achieve continuous transition from linear to square root at the transition point.
Note
Do not set both the analog output of the device and the control system to square root.
Reference Manual Configuration
00809-0100-4803 October 2018
Emerson.com/Rosemount 61