Understanding How Routing Tables Are Used - Allen-Bradley AB QUALITY ControlLogix 1756 Series User Manual

Understanding How Routing
Tables Are Used
In some of the example applications, you will need to use routing tables to
route messages between the PLC-5/40C processors if you include a
1756-DHRIO module in the path.
Important: You only need to create a routing table if the message path
includes a 1756-DHRIO module. Ethernet and ControlNet
modules do not require routing tables; however, if a message
path contains a mix of Ethernet, ControlNet, and DH+ network
segments, you must assign each of the network segments in the
path (including ControlNet and Ethernet network segments) a
link number.
Routing tables are stored in 1756-DHRIO modules. Each table contains all
of the "links" (i.e., network segments) in the message path from the source
of the message to the destination of the message. You assign a unique link
number to each of the network segments in the path. Link numbers range
from 1-199.
Important: Do not confuse link numbers with module port numbers or
node numbers. You configure link numbers using software
when you configure the system.These numbers appear only in
1756-DHRIO routing tables. Module port numbers are fixed for
ControlLogix Gateway modules as follows:
1756-DHRIO Modules:
Port Number:
1 backplane
2 channel A
3 channel B
1756-CNB Modules
Port Number:
1 backplane
2 either of the two ControlNet media ports
1756-ENET Modules
Port Number:
1 backplane
2 either of the two Ethernet media ports
In the example applications, you set module node numbers by using the
hardware switches on the 1756-CNB or -CNBR and on the 1756-DHRIO
modules.
Overview
Port:
Port:
Port:
Publication 1756-6.5.13 - September 1999
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