Siemens LR 460 Benutzerhandbuch
Page J-100
SITRANS LR 460 (PROFIBUS PA) – INSTRUCTION MANUAL
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Description of the blocks
Level Transducer Block function groups
The figure below shows the signal flow of measured values from the sensor through the
Level Transducer Block into the output value (Primary Value/ Level; Secondary Value 1 /
Level; or Secondary Value 2 /Distance. The LTB implements all of the basic parameters
(see parameter diagram on page 101).
Level Transducer Block into the output value (Primary Value/ Level; Secondary Value 1 /
Level; or Secondary Value 2 /Distance. The LTB implements all of the basic parameters
(see parameter diagram on page 101).
1
How the Level Transducer Block works:
1.
The sensor technology block selects the proper echo. See
72 for more detail.
The sensor value (in sensor units) is checked to see if it is within its measuring limits.
If the limit is exceeded, this results in a Bad status and the error message Failure in
measurement. The sensor value is stored in Sensor Value.
measurement. The sensor value is stored in Sensor Value.
The analog signal from the sensor is transformed into a digital signal.
A Sensor Offset (default 0) provides compensation if necessary for differences
A Sensor Offset (default 0) provides compensation if necessary for differences
between the vessel reference point and the sensor reference point.
Note: Primary Value (PV) is the default measured value; Secondary Value 1 (SV1) is an
equivalent value.
equivalent value.
1.
A Linearization module is required by the PROFIBUS PA specifications. The
Linearization block is turned off in SITRANS LR 460.
Linearization block is turned off in SITRANS LR 460.
Level Transducer Block
Sensor Value
(sensor units)
Sensor
Sensor
technology
Level
calibration
Linearization
(turned off)
(turned off)
Level
(level units)
Primary Value
Level
(level units)
(Analog
Input)
AIFB1
Secondary Value 1
[Level]
(Level Units)
Secondary Value 2
[Distance]
(Sensor Units)
Sensor
Offset
Level
Offset
High
Calibration
Point
High Level
Point
Low
Calibration
Point
Low Level
Point
Calibration
Type
Linearization
Type
PV
SV1
SV2
AIFB2
(Analog
Input)