Description Of The Blocks; Level Transducer Block Function Groups - Siemens Sitrans PROBE LU Instruction Manual

Analog Input Function Blocks AIFB1 and AIFB2
The two Analog Input Function Blocks are completely independent of each other. They
use the output from the Level Transducer Block, and apply any required quality checks,
scaling, and Failsafe operation selections.
The output of an Analog Input Function Block supplies the measured value and
associated status information to PROFIBUS PA, via cyclic data transfer.

Description of the blocks

Level Transducer Block function groups

The figure below shows the signal flow of measured values from the sensor through
the transducer block into the output value (Primary Value/ Level or Volume;
Secondary Value 1/Level; Secondary Value 2 /Distance 1; or Secondary Value 3/
Distance 2). The LTB implements all of the basic parameters (see parameter diagram
on page 57), including level to volume calculation, if that option has been selected.
Level Transducer Block
Sensor Value
Sensor
Sensor
technology
Sensor
Offset
Page 56 SITRANS Probe LU (PROFIBUS PA) – INSTRUCTION MANUAL
Level
Level
calibration
Level
Offset
High Low
Calibration Calibration
Point Point
High Level Low Level
Point Point
Sensor
Level unit
conversion
Primary Value
[Level/Volume]
(level/volume units)
PV
Linearization
Linearization
Type
SV1
Secondary Value 1
[Level]
(Level Units)
SV2
Secondary Value 2
[Distance 1]
(Sensor Units)
SV3
Secondary Value 2
[Distance 2]
(Level Units)
AIFB1
(Analog
Input)
AIFB2
(Analog
Input)
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