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Overview of I/O Memory Area Section 4-1
Note H512 to H1535 are used as a Function Block Holding Area. These words can
be used only for function block instances (internally allocated variable area).
These words cannot be specified as instruction operands in the user program.
Auxiliary Area (A) These words are allocated to specific functions in the system.
Refer to Appendix C Auxiliary Area Allocations by Function and Appendix D
Auxiliary Area Allocations by Address for details on the Auxiliary Area.
Temporary Relay Area
(TR)
The TR Area contains bits that record the ON/OFF status of program
branches. Refer to the CP1H Programming Manual for details.
Data Memory Area (D) The DM Area is a multi-purpose data area that is normally accessed only in
word-units. These words retain their content when the PLC is turned ON or
the operating mode is switched between PROGRAM mode and RUN or MON-
ITOR mode.
Timer Area (T) There are two parts to the Timer Area: the Timer Completion Flags and the
timer Present Values (PVs). Up to 4,096 timers with timer numbers T0 to
T4095 can be used.
Timer Completion Flags
These flags are read as individual bits. A Completion Flag is turned ON by the
system when the corresponding timer times out (i.e., when the set time
elapses).
A447
A448
A959
15
Read-write area
Read-only area
Word
Bit
D00000
D20000
D29599
D30000
D31599
D32767
Special I/O Unit DM Area
(100 words/Unit)
CPU Bus Unit DM Area
(100 words/Unit)
Word
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