KROHNE H250 M40 PROFIBUS PA - Manual (Page 5)

PROFIBUS PA
2
5
H250 M40 ESK4
www.krohne.com 03/2014 - 4002251801 - AD H250/M40 PROFIBUS R01 en
2.3 PROFIBUS PA Profile implementation
The PROFIBUS PA Profile 3.02 defines standardized parameters and functions for PROFIBUS
devices used for process control. It describes a PROFIBUS device as a function block application,
i.e. parameters and functions are grouped into different blocks. In the ESK4-PA transmitter the
following blocks are implemented:
The Analog Input Function Block and the Totalizer Function Blocks provide the data interface
towards a process control system (e.g. a PLC); i.e. their input/output data can be read/written by
the control system. In a PROFIBUS network this is done via cyclic communication services.
From the PROFIBUS point of view the ESK4-PA transmitter is designed as a modular device with
three slots. While the Analog Input Function Block is assigned (as virtual module) to slot 1 the
Totalizer Function Blocks are assigned (as virtual modules) to slot 2 and 3. This assignment is
fixed and cannot be modified by the user. Nevertheless the measuring data for each Function
Block is selectable according to the following tables:
Device calibrated for Volume Flow
The calibration units are used as default units.
Block Usage
1 Physical Block (PB) contains identification and diagnosis parameters of the device
1 Flow Transducer Block
(TB-Flow)
contains parameters and functions to control the flow measurement
1 Level Transducer Block
(TB-Level)
contains parameters and functions to control the level measurement
1 Analog Input Function Block
(AI-FB)
contains parameters and functions to control the measuring output;
provides the measuring value(s)
2 Totalizer Function Blocks
(Tot-FB)
contains parameters and functions to control/provide the counter
value(s)
Slot Slot Slot Slot Module type Module type Module type Module type Measuring data Measuring data Measuring data Measuring data 1
1 AI-FB Volume flowrate (Default setting)
Mass flowrate
Board temperature
2 Totalizer-FB Totalized volume flowrate (Default setting)
Totalized mass flowrate
3 Totalizer-FB Totalized volume flowrate
Totalized mass flowrate (Default setting)
1 Selection of measuring data can be changed by modifying the channel parameter via acyclic PROFIBUS services.
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