Calibration - Honeywell ST700 User Manual

Level Calculation Formula
The level is calculated in the following way:
V = 100 • [C + (C
0
Where:
•
V = Volume (%)
•
H = height of process tank fluid, in fraction (0.0 - 1.0) of TANK_RANGE
•
C = LEVEL_COEFF[i]
i
ATTENTION
Note that the coefficients must be provided for this equation, as the
transmitter has no knowledge of the shape of the tank.
The result of the calculation, V is placed in CALC_VAL and passed to the AI
block. The engineering units are always expressed as a percent (%).

Calibration

Calibration is performed in order to get the precise value. If there is any offset in value it
can be eliminated by performing calibration. For example, if zero pressure is applied, but
the sensor indicates a value of 0.1, then it can be made zero by performing calibration.
Hence, when zero pressure is applied next time, it indicates exactly zero.
ATTENTION
Note that calibration is performed only for the primary variable.
Calibration methods
There are 4 types of sensor calibrations: LRV Correct, URV Correct, Zero correct, and
Corrects Reset.
LRV Correct
LRV Correct is used to correct the Lower range value. For LRV correct, use
CAL_POINT_LO.
Page 28 FOUNDATION Fieldbus ST 700 Pressure Transmitter User's Guide
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• H ) + (C • H ) + (C
1 2 3
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• H ) + (C • H ) + (C • H
4 5
5
)]
Revision 2.0