J DF 3 0 0 |
FI EL D I N D I C ATO R | O I/J D F 3 0 0 - EN R E V. B
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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
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
OUT
IN_2
IN_3
IN_1
IN_LO
AR
IN
IN_2
IN_3
IN_1
IN_LO
RANGE_HI
RANGE_LO
PV
ARITH_TYPE
BAL_TIME
func
OUT_HI_LIM
OUT_LO_LIM
OUT
RANGE
EXTENSION
FUNCTION
ALGORITHM
TYPE
* GAIN
+ BIAS
COMP_LO_LIM
COMP_HI_LIM
GAIN_IN_1
(IN_1+BIAS_IN_1)*GAIN_IN_1
(IN_2+BIAS_IN_2)*GAIN_IN_2
(IN_3+BIAS_IN_3)*GAIN_IN_3
BIAS_IN_1
t_1
t_2
t_3
