X20 system modules • X20 electronics module communication • X20CS1012
X20 system User's Manual 3.10
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4.18.3.8.3 General information
The M-Bus standard is a serial bus system that handles half-duplex or asynchronous communication. The high level
of variability provided by this protocol enables a wide range of information to be handled via the same interface. In
basic M-Bus networks, the master communicates with up to 250 slaves via the "primary address". In later stages
of development, the secondary address (4 bytes) was then also specified. This made it possible to significantly
increase the number of slaves in a network.
Important information about the module
•
Generally: Primary address used (1 to 250)
•
Secondary address only supported via FlatStream
•
Bus can supply 64 slaves with power
4.18.3.8.4 Module configuration
The flexible design of the M-Bus protocol can quickly add up to a lot of configuration work. That's why B&R offers
two different user interfaces for the module: "Standard" and "FlatStream". The user-friendly B&R Standard interface
allows users to view up to eight values requested cyclically from the M-Bus network. In FlatStream mode, the
module acts as a bridge between the PLC and the M-Bus slave, which makes all M-Bus functions available.
Information:
The B&R Standard interface is statically configured and based on cyclic registers. Because X2X Link
can only transfer a certain number of values cyclically, the user must make his selection accordingly.
4.18.3.8.4.1 Settings for operation
Name:
CfO_FunctionModel
This register can be used to enable either the Standard or FlatStream interface, which makes the module much
more efficient.
Data type
Value
UINT
See bit structure.
Bit structure:
Bit
Name
Value
Information
0
Disabled
0
B&R Standard Interface
1
Enabled
0
Disabled
1
FlatStream
1
Enabled
3 - 7
Reserved
0
