User manual

Publication CNET-UM001C-EN-P - November 2005

Determine Your ControlNet Media Requirements C-19

Figure C.9

Node

Trunk Cable A =

43630

Trunk Cable B =

Node

Terminators

Trunk Cable A =

Trunk Cable B =

Terminators

Repeater B

Terminators

Segment 1

Segment 2

Repeater A

To use redundant media, all nodes must support redundant media.

IMPORTANT

Make sure you do not mix A and B cable connections in a

redundant operations. A node supporting redundant

trunk-cable connections will function even if trunk cable A

is connected to the B connector on the node and

vice-versa. However, this makes cable fault indications (on

the hardware or in software) difficult to interpret and

makes locating a bad cable segment extremely difficult.

When in redundant cable mode, each node independently

decides whether to use channel A or channel B. This

decision is based on error counters internal to each node.

Redundant cabling is only valid if there is only one fault on

the network. In other words, if you have a proper

redundant cabling system and you remove node 3 on trunk

A and node 4 on trunk B the system will not operate

correctly because a double failure has occurred.