Siemens SITRANS LR 300, Instruction Manual, Page: 121 / 140

7ML19985CL02 SITRANS LR 300 – INSTRUCTION MANUAL Page 119
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Appendix VII
Profibus Level Device Design
The device follows the profile block model and includes a physical block, a level
transducer block and four analog input function blocks.
Profile 3.0 Class A Design
The device is implemented as a Profile 3.0, Class A PA device. The Profile model is used,
but in order to program the level transducer block, you have to use some device-specific
parameters in addition to the standard profile parameters.
The Transducer Block (TB) implements some of the Class B parameters, but not all.
The outputs from the TB are the Level, Space, Distance and Volume values as calculated
by the device (P921, P922, P927 & P924). The output to the function blocks (FB’s) is always
in percent, except for Distance which is always in meters. The analog input FB’s can then
convert the percent values into any units desired.
Block Model
The device is implemented with one Physical Block (PB1), one Transducer Block (TB1)
and four Function Blocks (FB1, FB2, FB3, FB4).
Note:
the LCD display values are not the same as the Analog Input (AI) block outputs.
The AI block can perform any conversion to a value, which may be in different units
from the LCD.
Physical
Block
Device
Management
Profibus
Acyclic Data
Profibus
Cyclic Data
Level
Volume
Space
Distance
Level
Volume
Space
Distance
Level Transducer
Block
Class A
Sensor Value
(profile)
LCD
display
Function Block
Analog Input
Level
Class A
Function Block
Analog Input
Space
Class A
Function Block
Analog Input
Distance
Class A
Function Block
Analog Input
Volume
Class A
SITRANS LR 300.book Page 119 Monday, June 10, 2002 7:18 PM