Dynamic routing of messages – Schneider Electric 174 CEV User Manual
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Configuring the Bridge
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3.9
Dynamic Routing of Messages
In addition to the mapped routing of messages from TCP/IP to Modbus Plus,
messages can be dynamically routed in this direction at runtime. Dynamic routing
is available only to connections initiated fromTCP/IP.
The bridge reserves three Destination Indexes for dynamic routing. A TCP/IP host
node uses index 255 to set the bridge for two kinds of dynamic routing from that
host. Then the host uses indexes 0 (zero) or 254 to dynamically route messages.
Index 0 provides Host--based routing for up to 10 TCP/IP hosts concurrently.
Index 254 provides Socket--based routing for the duration of the host connection.
3.9.1
Setting Up the Bridge for Dynamic Routing
You must setup the bridge for dynamic routing before you can use it. Note that
dynamic routing is implemented at runtime and is not part of the bridge’s internal
configuration.
To setup the bridge for dynamic routing, address the bridge using its Destination
Index for an internal bridge command (255). Write the Modbus Plus destination
node’s five--byte routing path as data into one of these registers:
H
Register 1 for Host--based routing
H
Register 255 for Socket--based routing.
The data portion of the write command must contain three words in the form:
Example
The following example sets up a Host--based routing to a Modbus Plus node
destination on the routing path 30.18.9.37.2:
Word
Contents (Hex)
Contents (Decimal)
1
05 1E
05 30
2
12 09
18 09
3
25 02
37 02
Note that the five--byte routing path must be preceded with a byte (always
containing 05) to show the length in bytes of the routing path.