Arithmetic Function Block (Ar); Overview; Block Diagram; Description - ABB JDF300 Operating Instruction

J D F 3 0 0 | F I E L D I N D I C ATO R | O I/ J D F 3 0 0 - E N R E V. B

Arithmetic Function Block (AR)

Overview

This block is designed to permit simple use of popular measurement math functions. The user does not
have to know how to write equations. The math algorithm is selected by name, chosen by the user for the
function to be done.
The following algorithms are available selectable from ARTH_TYPE:
1. Flow compensation, linear.
2. Flow compensation, square root.
3. Flow compensation, approximate.
4. BTU flow.
5. Traditional Multiply Divide.
6. Average.
7. Traditional Summer.
8. Fourth order polynomial.
9. Simple HTG compensated level.

Block Diagram

IN
IN_LO
IN_1
IN_2
IN_3

Description

The AR block is intended for use in calculating measurements from combinations of signals from sensors.
It is not intended to be used in a control path, so it does not support control status propagation or back calculation. It has no
process alarms.
The block has 5 inputs. The first two are dedicated to a range extension function that results in a PV, with status reflecting the
input in use.
The remaining three inputs are combined with the PV in a selection of four term math functions that have been found useful in a
variety of measurements. The inputs used to form the PV should come from devices with the desired engineering units, so that the
PV enters the equation with the right units. Each of the additional inputs has a bias and gain constant.
IN
IN_LO
IN_1
IN_2
IN_3
RANGE_LO
RANGE_HI
RANGE PV
EXTENSION
FUNCTION
(IN_1+BIAS_IN_1)*GAIN_IN_1
(IN_2+BIAS_IN_2)*GAIN_IN_2
(IN_3+BIAS_IN_3)*GAIN_IN_3
GAIN_IN_1 BIAS_IN_1
AR OUT
ARITH_TYPE
BAL_TIME
ALGORITHM func
t_1
TYPE
t_2
t_3
COMP_LO_LIM
COMP_HI_LIM
OUT_HI_LIM
OUT
* GAIN
+ BIAS
OUT_LO_LIM
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