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I/O Memory Areas Section 9-2
Data Memory Area (DM) The DM Area is a multi-purpose data area that can be accessed in word-units
only. These words retain their content when the PLC is turned on or the oper-
ating mode is switched between PROGRAM mode and RUN or MONITOR
mode.
Extended Data Memory
Area (EM) (CJ1 and CJ1-H
CPU Units Only)
The EM Area is a multi-purpose data area that can be accessed in word-units
only. These words retain their content when the PLC is turned on or the oper-
ating mode is switched between PROGRAM mode and RUN or MONITOR
mode.
The EM Area is divided into 32,767-word regions called banks. The number of
EM banks depends upon the model of CPU Unit, with a maximum of 13 banks
(0 to C). Refer to
2-1 Specifications for details on the number of EM banks
provided in each model of CPU Unit.
Timer Area There are two timer data areas, the Timer Completion Flags and the Timer
Present Values (PVs). Up to 4,096 timers with timer numbers T0000 to T4095
can be used. The same number is used to access a timer’s Completion Flag
and PV.
Timer Completion Flags
These flags are read as bits. A Completion Flag is turned ON by the system
when the corresponding timer times out (the set time elapses).
Timer PVs
The PVs are read and written as words (16 bits). The PVs count up or down
as the timer operates.
D00000
D20000
D29599
D30000
D31599
D32767
Special I/O Unit Area
(10 words/Unit)
CPU Bus Unit Area
(100 words/Unit)
Word
E0_32767
E2_0000
E2_32767
E0_00000
Word
Word
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