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4-2SectionI/O Allocation
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IR words that are not allocated to inputs or outputs can be used as work words.
The work bits can be used freely within the program. They can only be used with-
in the program, however, and not for direct external I/O.
These bits mainly serve as flags for CPM2B operation or contain present and set
values for various functions. SR 253 to SR 255 are read-only. Refer to 4-3 SR
Area for details on the various bit functions.
When a complex ladder diagram cannot be programmed in mnemonic code just
as it is, these bits are used to temporarily store ON/OFF execution conditions at
program branches. They are used only for mnemonic code. When programming
directly with ladder diagrams using the Support Software, TR bits are automati-
cally processed for you.
The same TR bits cannot be used more than once within the same instruction
block, but can be used again in different instruction blocks. The ON/OFF status
of TR bits cannot be monitored from a Programming Device.
These bits retain their ON/OFF status even after the PC power supply has been
turned off or when operation begins or stops. They are used in the same way as
work bits.
These bits mainly serve as flags related to PC operation. These bits retain their
status even after the PC power supply has been turned off or when operation
begins or stops. Refer to 4-4 AR Area for details on the various bit functions.
When the CPM2B is linked 1:1 with another CPM2B or a CPM1/CPM1A/
CPM2A/CPM2C/SRM1(-V2), a CQM1, a C200HS or a C200HX/HG/HE PC,
these bits are used to share data.
LR words can be used as work words when they are not used for a 1:1 PC Link.
This area is used to manage timers and counters created with TIM, TIMH(15),
TMHH(––), TIML(––), CNT, and CNTR(12). The same numbers are used for
both timers and counters and each number can be used only once in the user
program. Do not use the same TC number twice even for different instructions.
Use TC numbers 000 to 003 for TIMH(15) and TC numbers 004 to 007 for
TMHH(––). When these timer numbers are used, timing is performed as an in-
terrupt process and the cycle time is not affected.
TC numbers are used to create timers and counters, as well as to access
Completion Flags and present values (PVs). If a TC number is designated for
word data, it will access the present value (PV); if it is used for bit data, it will ac-
cess the Completion Flag for the timer/counter.
DM area data is accessed in word units only. The contents of the DM area are
retained even after the PC power supply has been turned off or when operation
begins or stops.
DM words DM 0000 to DM 1999 and DM 2022 to DM 2047 can be used freely in
the program; other DM words are allocated specific functions.
DM 2000 to DM 2021 contain the error log information. Refer to Section 4-6 Error
Log for details on the error log.
DM 6600 to DM 6655 contain the PC Setup. Refer to 4-5 PC Setup for details.
4-2 I/O Allocation
IR bits are allocated to actual input terminals and output terminals on the CPU
Board and Expansion I/O Boards. IR words that are not allocated to inputs or
outputs can be used as work words.
Work Bits
SR Area
TR Area
HR Area
AR Area
LR Area
Timer/Counter Area
DM Area