User's Manual

Page 124 SITRANS LR560 (PROFIBUS PA) – OPERATING INSTRUCTIONS 7ML19985LT01
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E: Profile structure
Appendix E: PROFIBUS PA Profile
Structure
PROFIBUS Level Device Design
The device follows the profile block model and is implemented as a Profile 3.01, Class B,
PA device. Standard profile parameters are used to program the level transducer block.
Block Model
The Block Model represents how measured values are recorded and processed. All data
is viewed from the perspective of the DCS or PLC, so information from the sensor is an
input.
The functions of the device are divided into blocks with different areas of responsibility.
The blocks are configured by parameters.
The device is implemented with one Physical Block, one Transducer Block (TB), and two
Analog Input Function Blocks (AIFB1 and AIFB2).
Physical Block
The Physical Block handles functionality and descriptions relating to the device as a
whole: for example, LCD Contrast (functionality) and Firmware Revision and Tag
(descriptions).
Transducer Block (TB)
The Transducer Block carries out adjustments to the sensor, such as level calibration (and
volume calibration, if supported). It supplies the measured value
1)
utilized by either or
both of the AIFBs.
Analog Input Function Blocks AIFB1 and AIFB2
The two AIFBs are identical and completely independent of each other. They utilize the
measured value
1)
output from the Transducer Block and apply any required quality
checks, scaling, and Fail-safe operation selections.
The output from the Analog Input Function Block supplies the measured value with
associated status information to the PROFIBUS PA network via cyclic data transfer.
1)
Primary Value (PV), Secondary Value 1 (SV1), or Secondary Value 2 (SV2)
sensor
sensor
Transducer Block
electronics
temperature
Analog Input
Function Block2
Analog Input
Function Block1
PROFIBUS PA