User's Manual

7ML19985LT01 SITRANS LR560 (PROFIBUS PA) – OPERATING INSTRUCTIONS Page 125
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E: Profile structure
Description of the blocks
Transducer Block
The figure below shows the signal flow of measured values from the sensor through the
Transducer Block into the output value:
•Primary Value (PV)
1)
: Level (or Volume, if supported. LR560 does not support
volume).
• Secondary Value 1 (SV1): Level
• Secondary Value 2 (SV2): Distance
The Transducer Block implements all of the basic parameters of the PROFIBUS profile
standard (illustrated in step 2 below).
How the Transducer Block works:
1) The sensor technology sub-block selects the proper echo. For an explanation of
sensor technology, see Appendix D: Technical Reference , page 115 onwards.
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.
The analog signal from the sensor is transformed into a digital representation.
A Sensor Offset (default 0) compensates for changes to the sensor reference point,
if necessary.
(continued on next page)
1)
PV output is provided for PROFIBUS Profile for Process Devices 3.01 compatibility.
Transducer Block
Sensor Value
Sensor
Sensor
technology
Level
calibration
(no
Linearization)
Level Primary Value
[Level/Volume]
(volume not
supported)
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
PV
SV1
SV2
AIFB2
(Analog
Input)