Installation guide

Introducing the Modbus Plus Network

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1.12 Joining Modbus Plus Networks

1.12.1 How the Bridge Plus Operates

The BP85 Bridge Plus device connects as a node on each of two Modbus

Plus networks. The Bridge operates as an independent node on each

network, receiving and passing tokens according to each network’s

address sequence. Bridge Plus devices are not applicable to networks

used for Distributed I/O applications.

Figure 19 shows three networks (A, B, and C) joined by a pair of Bridge

Plus devices. The figure shows a single-cable network for simplicity.

The Bridge Plus also supports dual-cable layouts. One Bridge appears

on network A at node address 22, and on network B at node 25. The

other Bridge is on network B at node 20, and on network C at node 20.

Note that each Bridge’s two network addresses are entirely separate,

and can be set uniquely for each network.

NETWORK A

NETWORK B

NODE

BP85

BRIDGE

PLUS

NODE NODE

NODE

NETWORK C

NODE

NODE NODE NODENODE

NODE

BP85

BRIDGE

PLUS

Figure 19 Message Routing Through Multiple Networks