Compensating For Span Line Pressure Effects (Range 4 And 5) - Emerson Rosemount 2051 Reference Manual

Reference Manual
00809-0100-4107
4. Calculate the stability per month.
5. Calculate calibration frequency.
5.6 Compensating for span line pressure effects
(range 4 and 5)
Rosemount 2051 Range 4 and 5 Pressure Transmitters require a special calibration
procedure when used in differential pressure applications. The purpose of this procedure is
to optimize transmitter performance by reducing the effect of static line pressure in these
applications. The Rosemount Differential Pressure Transmitters (ranges 1 through 3) do
not require this procedure because optimization occurs at the sensor.
The systematic span shift caused by the application of static line pressure is –0.95 percent
of reading per 1000 psi (69 bar) for Range 4 transmitters and –1 percent of reading per
1000 psi (69 bar) for Range 5 transmitters. Using the following procedure, you can correct
the span effect to ±0.2 percent of reading per 1000 psi (69 bar) for line pressures from 0 to
3626 psi (0 to 250 bar).
Use the following example to compute correct input values.
5.6.1 Example
To correct for systematic error caused by high static line pressure, first use the following
formulas to determine the corrected values for the high trim value.
High trim value
HT = (URV – [S/100 ×P/1000 × LRV])
Where:
In this example:
URV =
S =
Reference Manual
Note
Zero static pressure effect removed by zero trimming at line pressure.
HT = Corrected high trim value
URV = Upper range value
S = Span shift per specification (as a percent of reading)
P = Static Line Pressure in psi
1500 inH O (3.74 bar)
2
–0.95%
Operation and Maintenance
September 2020
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