Omron CJ2 CPU UNIT SOFTWARE User Manual page 73

Memory Status after Mode Changes and Power Interruptions
Some parts of I/O memory, such as the CIO Area and Work area, will be cleared when the operating
mode is changed between RUN or MONITOR mode and PROGRAM mode. These are called non-hold-
ing areas. To hold the contents of these areas when the operating mode is changed, turn ON the IOM
Hold Bit (A500.12) in the Auxiliary Area
Mode change
RUN or MONITOR to
PROGRAM
PROGRAM to RUN
or MONITOR
RUN to MONITOR or
MONITOR to RUN
Power interruption
*2
reset
*1 Memory is cleared on if the IOM Hold Bit is OFF. If it is ON, data will be held as follows:
I/O Memory
Hold Bit sta-
tus (A500.12)
OFF Cleared
Held
ON
*2 The IOM Hold Bit (A500.12) will be turned OFF when a power interruption is reset. To retain the status, select
the IOM Hold Bit Check Box in the Startup Hold Settings Tab Page of the PLC Setup using the CX-Program-
mer, and then transfer the PLC Setup.
*3 The Task Flags will be cleared regardless of the status of IOM Hold Bit (A500.12).
CJ2 CPU Unit Software User's Manual
Non-holding areas
• I/O Area
• Data Link Area
• CPU Bus Unit Area
• Special I/O Unit Area
• Work Area
• Timer PV and Completion Flags
• Index Registers
• Data Registers
• Task Flags
(Auxiliary Area bits/words are held or not
held depending on the address.)
*1
Cleared
Held
*3
Cleared
I/O Memory
Mode Fatal error
changed
between
Fatal error
PROGRAM
other than
and
FALS
RUN/MONI-
TOR
Cleared
Held
• HR Area
• DM Area
• EM Area
• Counter PV and Completion Flags
(Auxiliary Area bits/words are held or not
held depending on the address.)
Held
Held
Held
Output bits allocated to Output Units
Mode
changed
between
PROGRAM
FALS
and
executed
RUN/MONI-
TOR
Held OFF
Held Held
3 CPU Unit Operation
Holding Areas
Fatal error
Fatal error
FALS
other than
executed
FALS
OFF OFF
OFF:
Values in the I/O memory in
the CPU Unit will be held when
a fatal error occurs, but the
outputs from Basic Output
Units will turn OFF.
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