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Cabling, Addressing and placing i/o, Cabling -2 addressing and placing i/o -2 – Rockwell Automation 1785-Lxxx Enhanced and Ethernet PLC-5 Programmable Controllers User Manual

Page 120

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Publication 1785-UM012D-EN-P - July 2005

8-2 Communicating with Extended-Local I/O

Cabling

The maximum cable length for an extended-local I/O system is
30.5 cable-m (100 cable-ft). Connect extended-local I/O adapters by using any
of these cables:

Addressing and Placing I/O

When a PLC-5/40L or -5/60L controller is used to scan both extended-local
I/O and remote I/O racks, the total of both remote I/O and extended-local
I/O racks must not exceed the maximum number of racks allowed for the
controller (16 racks for a PLC-5/40L or 24 racks for a PLC-5/60L). shows a
PLC-5/40L controller controlling both extended-local I/O and remote I/O
racks.

Cable Length

Catalog Number

1 m (3.3 ft)

1771-CX1

2 m (6.6 ft)

1771-CX2

5 m (16.5 ft)

1771-CX5

IMPORTANT

You cannot connect or splice extended-local I/O cables to
form a custom cable length. For example, if you have a
distance of 4 m between two extended-local I/O adapters
or between a controller and an extended-local I/O adapter,
you cannot connect two 2 m cables together. You would
have to use the 5 m cable and have the extra 1 m as slack.

Terminate the link by installing the local I/O terminator
(1771-CXT) on the last adapter module. The system will
not run without it. The terminator is included with the
controller.