Analog Input Block; Execution; Figure 12: Analog Input Block - Honeywell SLG 700 Option Manual

3.9 Analog Input block

The Analog Input (AI) block takes the transducer's input data, selected by channel number, and makes
it available to other function blocks at its output. The variables to be used by the block are defined
through the available channels:

Product Level

Distance To Product

Product Level Rate

Interface Level

Distance To Interface

Interface Level Rate

Vapor Thickness

Execution

3.9.1. Transmitter Output Signal and Status
Viewing certain parameters, their values and status in the transmitter and understanding their
relationship to each other are helpful in understanding transmitter output signal and status. The
following paragraphs and tables describe transducer and AI block parameters which directly determine
the way the transmitter output is presented.
Level Sensor Signal
In Transducer block, the Surface Signal or Interface Signal is represented as calculated Distance to
Level and Distance to Interface Values. These values are used to calculate the Product Level, Interface
Level, Vapor Thickness and Upper Product Thickness. These values use Level use the elements in
Product Level Range to determine the engineering units, the decimal places for the display and also
the high and low scale of the value. This Product Level and Interface Level values are further used to
calculate the Product Level Rate and Interface Rate which use the elements in Level Rate Range to
determine the engineering units and Product Volume, Vapor Volume, Upper Product Volume and
Lower Product Volume which use the Product Volume Range to determine the engineering units,
decimal places for the display and also the high and low scale of the value. These values become the
PV value in the AI block, and uses the elements of OUT_SCALE in determining the units, decimal
places and also the high and low scale values of PV. These signal leave the AI block as OUT value,
which also uses the elements of OUT_SCALE.
The Transducer scaling (XD_SCALE) is applied to the value from the channel to produce the
FIELD_VAL in percent. The XD_SCALE unit's code must match the channel unit's code or be
supported by the device if this is not the case the block remains in OOS mode, after being configured.
Page 70

Figure 12: Analog Input Block

FOUNDATION Fieldbus Option User's Manual

Product Volume

Electronic Temperature

Vapor Volume

Upper Product Volume

Lower Product Volume

Upper Product Thickness
Rev.5