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Appendix D
Memory Areas
Overview
The following table shows the data areas in PC memory.
Area Size Range Comments
I/O Area 480 bits IR 000 to IR 029
Group-2 High-density
I/O Unit Area
320 bits IR 030 to IR 049 Can be used as ordinary I/O or, if not used for
real I/O, can be used as work bits.
SYSMAC BUS Area 800 bits IR 050 to IR 099 Can be used as work bits if not used for real I/O.
Special I/O Unit Area 1,600 bits IR 100 to IR 199 ”
Optical I/O Unit Area 512 bits IR 200 to IR 231 ”
Work Area 1 64 bits IR 232 to IR 235
Special Relay Area 1 320 bits SR 236 to SR 255
Special Relay Area 2 704 bits SR 256 to SR 299
Macro Area
64 bits SR 290 to SR 293 Inputs
64 bits SR 294 to SR 297 Outputs
Work Area 2 3,424 bits IR 298 to IR 511
Temporary Relay Area 8 bits TR 00 to TR 07
Holding Relay Area 1,600 bits HR 00 to HR 99
Auxiliary Relay Area 448 buts AR 00 to AR 27
Link Relay Area 1,024 bits LR 00 to LR 63
Timer/Counter Area 512 counters/
timers
TC 000 to TC 511 TIM 000 through TIM 015 can be refreshed via
interrupt processing as high-speed timers.
Data Memory Area
6,144 words DM 0000 to DM 6143 Read/Write
y
1,000 words DM 0000 to DM 1999 Special I/O Unit Area (see note)
31 words DM 6000 to DM 6030 History Log
(44 words) DM 6100 to DM 6143 Link test area (reserved)
512 words DM 6144 to DM 6655 Fixed DM Area (read only)
456 words DM 6144 to DM 6599 (SYSMAC NET Area)
56 words DM 6600 to DM 6655 PC Setup
Expansion DM Area 3,000 words max. DM 7000 to DM 9999 Read only
I/O Comment Area All UM Area max. --- Stores I/O comments in the user program. Must
be set using LSS.
Ladder Program Area All UM Area max. --- Stores the user program executed by the CPU.
The program is retained even after the power
supply is turned off.
Note The PC Setup can be set to use DM 7000 through DM 7999 as the Special I/O Area.