I/O Allocations - Omron CJ2 CPU - REV 10-2010 User Manual

8 I/O Allocations and Unit Settings
8-1

I/O Allocations

8-1-1 I/O Allocations
Allocating words in I/O memory in the CPU Unit for exchanging data between the CPU Unit and other
Units is called I/O allocation. Memory is allocated differently to Basic I/O Units, Special I/O Units, and
CPU Bus Units.
Basic I/O Units
Memory is allocated in units of 16 bits
CPU Bus Units
Special
Units
25 words allocated per Unit
Special I/O Units
10 words allocated per Unit
8-2
Allocations
OD211
0 1 2 3 4 5 6 7
8 9 10 11 12 13 14 15
The words that are allocated
are determined by the position
of the Unit.
The words that are allocated
are determined by the unit number.
SCU41
RUN ERC SD1 RD1 TER1
RDY
ERH SD2 RD2
TERM
OFF
ON
UNIT
NO.
WIRE
2 4
The words that are allocated
PORT1
(RS422
/485)
are determined by the unit number.
PORT2
*1 The first word on each Rack can be set from the CX-Programmer to an address
between CIO 0000 and CIO 0999 (default setting: consecutive allocation from
CIO 0000).
I/O Memory Areas in CPU Unit
CIO 0000
I/O Area
CIO 0159
CIO 1000
CIO 1500
CPU Bus Unit Area
CIO 1899
CIO 2000
Special I/O Unit Area
CIO 2959
CJ2 CPU Unit Software User's Manual
*1