Siemens sitrans PROBE LU User Manual

Page 56 SITRANS Probe LU (PROFIBUS PA) – INSTRUCTION MANUAL 7ML19985JB02
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F: Profile structure
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
Level
calibration
Linearization
Level Primary Value
[Level/Volume]
(level/volume units)
(Analog
Input)
AIFB1
Secondary Value 1
[Level]
(Level Units)
Secondary Value 2
[Distance 1]
(Sensor Units)
Sensor
Offset
Level
Offset
High
Calibration
Point
High Level
Point
Low
Calibration
Point
Low Level
Point
Linearization
Typ e
Secondary Value 2
[Distance 2]
(Level Units)
Sensor
Level unit
conversion
PV
SV1
SV2
SV3
AIFB2
(Analog
Input)

Siemens sitrans PROBE LU Specifications

General

Measuring Principle	Ultrasonic
Communication	HART
Output	4 to 20 mA
Power Supply	12 to 30 V DC
Process Temperature	-40 to 80 °C
Enclosure Rating	IP68
Material	PVDF
Ambient Temperature	-40 to 70 °C
Measurement Range	0.25 to 12 m (0.8 to 39 ft)