Omron CP1L CPU UNIT - 06-2007 Operation Manual page 157

Overview of I/O Memory Area
Work Area (W)
Holding Area (H)
124
1:1 Link Area
These bits are used by the 1:1 Link Master and Slave. They are used for data
links between CP1L CPU Units and CPM2@ CPU Units.
Serial PLC Link Area
These words are allocated for use for data links (Serial PLC Links) with other
CP1L CPU Units or CP1H CPU Units. Addresses not used for Serial PLC
Links can be used in programming.
Internal I/O Area
These words can be used in programming; they cannot be used for I/O
exchange with external I/O terminals. Be sure to use the work words provided
in the Work Area before using words in the Internal I/O Area or other unused
words in the CIO Area. It is possible that these words will be assigned to new
functions in future versions of the CPU Units. The parts of the CIO Area that
are labelled "Not used" are functionally identical to the Internal I/O Area.
Words in the Work Area can be used in programming; they cannot be used for
I/O exchange with external I/O terminals. Use this area for work words and
bits before any words in the CIO Area.
Word
15
W511
Note These words should be used first in programming be assigned to new func-
tions in future versions of CP1L CPU Units.
Words in the Holding Area can be used in programming. These words retain
their content when the PLC is turned ON or the operating mode is switched
between PROGRAM mode and RUN or MONITOR mode.
Word
15
H511
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.
Bit
Bit
Section 4-1