Arithmetic Block; Execution; Figure 20: Arithmetic Block - Honeywell SLG 700 Option Manual

3.13 Arithmetic block

The Arithmetic block is designed for using popular measurement math functions easily. The math
algorithm is selected by name and the type of function to be performed. The block is used for
calculating measurements from a combination of signals from the sensors. The block must not be used
in a control path. The block does not support process alarms.
The Arithmetic block supports the following functions:

Flow compensation, linear

Flow compensation, square root

Flow compensation, approximate

BTU flow

Traditional Multiply Divide

Average

Traditional Summer
 Fourth order polynomial

Simple HTG compensated level

Fourth order Polynomial Based on PV

Execution

The block has five inputs, namely IN, IN_LO, IN_1, IN_2, and IN_3. The first two inputs (IN,
IN_LO) are designed for a range extension function that results in a Process Variable (PV), with the
status indicating the input in use.
The remaining three inputs (IN_1, IN_2, and IN_3) are combined with the PV in a selection of four
term math functions. To ensure that the PV enters the equation with the right units, the inputs used to
form the PV must come from devices with the desired engineering units. Each additional input has a
bias constant and gain constant. To correct Absolute Pressure, use the bias constant, and to normalize
terms within a square root function, use the gain constant.
Rev.5

Figure 20: Arithmetic Block

FOUNDATION Fieldbus Option User's Manual Page 99