Ar (Arithmetic) Function Block; General; Inputs/Outputs Of Ar Function Block - GE FVP110 Maintenance Manual

AR (Arithmetic) Function Block

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General

The AR (Arithmetic) block (Figure 68) contains math functions that are selected by name.
Figure 68 Inputs/Outputs of AR Function Block
The block has five 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. The bias can be used to correct for absolute temperature or pressure. The gain
can be used to normalize terms within a square root function. The output also has gain and
bias constants for any further adjustment required.
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.
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