20 
Appendix B. Change of unit area allocation 
This section describes the differences in unit area allocation between C200HX/HG/HE and CJ2.   
Refer to related manuals for details. 
Basic I/O 
"Free location and fixed word allocation" 
"Free location and free word allocation" 
Change the word and bit addresses 
 
Special I/O 
 
IR 400 to IR 459 
(10 words allocated for each Unit No.) 
DM 1000 to DM 2599 
(100 words allocated for each Unit No.) 
(10 words allocated for each Unit No.) 
D20000 to D21999 
(100 words allocated for each Unit No.) 
Change the word and bit addresses 
used in the program. 
CJ2H-CPU6â–¡-EIP/CJ2H-CPU
6
â–¡/CJ2M-CPUâ–¡â–¡   
SYSMAC CJ SERIES CJ2 
CPU UNIT SOFTWARE 
USER'S MANUAL (Cat. No. 
W473) for details on I/O 
Group-2 
High-density I/O 
IR 330 to IR 341 
(2 or 4 words allocated for each I/O 
word) 
The allocation is decided in the same 
way as Basic I/O Units depending on 
the installed position (rack and slot). 
Change the word and bit addresses 
PC Link cannot be used with 
CJ2. 
(SR) 
 
Auxiliary Relay Area 
(AR) 
SR 256 to SR 299 
 
AR 00 to AR 27 
(1) Auxiliary Area and bits 
Change the word and bit addresses 
used in the program. 
(2) Condition flags and clock pulses 
Change the arithmetic flags in the 
program to the condition flags. Clock 
pulses are specified using global 
symbols, such as "P_0.1ms" and 
In CJ2, operation flags and 
condition flags are specified 
by labels. 
SR 247 to SR 250 
(In SR Area) 
PC Link cannot be used with 
CJ2. 
Optical I/O Unit and 
I/Terminal Area 
The Optical I/O Unit cannot 
be used with CJ2. 
SYSMAC BUS Area 
IR 350 to IR 399 
CIO 3200 to CIO 3799 
[SYSMAC BUS Area] 
used with CJ2. 
IR 342 to IR 349 
CIO 3800 to CIO 6143 
Temporary Relay Area 
(TR) 
Change the program if the 
Error Log Area is read in the 
 
Appendix C. Change in PLC Settings 
Always uses the DM Area (DM 6600 to 
DM 6655 
Uses dedicated area for PLC settings 
(there is no address for setting by 
Refer to related manuals for 
details. 
 
Appendix D. Change of execution timing etc. 
method and execution 
timing 
Write interrupt programs in subroutines. 
Write interrupt programs in interrupt 
tasks. 
In CJ2, interrupt tasks are 
executed even when an 
instruction is being executed 
or I/O is being refreshed. 
I/O tables must be created with the 
CX-Programmer or other programming 
The cycle time is shortened with CS1.   
If the system operation is affected by 
cycle time, check the operation after 
To keep the same cycle time 
as C200HX/HG/HE, set 
Minimum Cycle Time in the