I/O Allocations; Cpu Bus Units; Unit Types - Omron CJ - 08-2008 Operation Manual

I/O Allocations

8-1

I/O Allocations

8-1-1

Unit Types

344
With a CJ-series PLC, the CPU Unit can automatically allocate I/O words to
the Basic I/O Units that are started and start operation automatically when the
power supply is turned ON. Words will be allocated to Special I/O Units and
CPU Bus Units according to the unit numbers set on the Units.
To help prevent troubles from occurring when adding Units or when the wrong
Unit is mounted, I/O tables can also be registered in the CPU Unit. (Refer to 8-
2 Creating I/O Tables for details.)
Memory is allocated differently to Basic I/O Units, Special I/O Units, and CJ-
series CPU Bus Units.
Basic I/O Units
OD211
Special I/O Units

CPU Bus Units

SCU41
RUN ERC SD1 RD1
TER1
RDY
ERH SD2 RD2
TERM
OFF
ON
UNIT
NO.
WIRE
2 4
PORT1
(RS422
/485)
PORT2
I/O Area
CIO 0000 to CIO0079
Words are allocated as required
by each Unit in sequence to
Units in the order they are
connected.
Allocations
Note: The first word on each Rack can be set from the CX-
Programmer to an address between CIO 0000 and
CIO 0999 to change the default setting
(consecutively from CIO 0000).
Special I/O Unit Area
CIO 2000 to CIO 2959
Words are allocated ten at a
time to each Unit according to
unit number.
Allocations
Note: The maximum total number of Units
that can be connected is 40, which means the
maximum number of Special I/O Units is 40.
CPU Bus Unit Area
CIO 1500 to CIO 1899
Words are allocated 25 at a time
to each Unit according to unit
number.
Allocations
Section 8-1