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CPU Unit Operating Modes Section 10-2
Note 1. The I/O memory is held or cleared according to the status of the IOM Hold
Bit and the setting for IOM Hold Bit Status at Startup in the PLC Setup
(read only when power is turned ON).
Mode Change: Between PROGRAMMING mode and RUN or MONITOR
mode
2. The forced status held or cleared according to the status of the Force Sta-
tus Hold Bit and the setting for Forced Status Hold Bit Status at Startup in
the PLC Setup.
Mode Change: Between PROGRAMMING mode and MONITOR mode
3. If the CPU Unit is turned OFF after online editing before the backup pro-
cess has been competed, an attempt will be made to recover the program
when power is turned ON again. The BKUP indicator will light during this
process. Refer to the CS/CJ Series Programming Manual (W394) for de-
tails.
10-2 CPU Unit Operating Modes
10-2-1 Operating Modes
The CPU Unit has three operating modes that control the entire user program
and are common to all tasks.
PROGRAM: Programs are not executed and preparations, such as creat-
ing I/O tables, initializing the PLC Setup and other settings,
transferring programs, checking programs, force-setting and
force-resetting can be executed prior to program execution.
MONITOR: Programs are executed, but some operations, such as online
editing, forced-set/reset, and changes to present values in I/O
memory, are enabled for trial operation and other adjust-
ments.
RUN: Programs are executed and some operations are disabled.
Auxiliary bit
PLC Setup setting
IOM Hold Bit (A50012)
Clear (OFF) Hold (ON)
IOM Hold Bit Status
at Startup
(Programming Con-
sole address:
Word 80, bit 15)
Clear
(OFF)
At power ON: Clear
At mode change: Clear
At power ON: Clear
At mode change: Hold
Hold
(ON)
At power ON: Hold
At mode change: Hold
Auxiliary bit
PLC Setup setting
Forced Status Hold Bit (A50013)
Clear (OFF) Hold (ON)
Forced Status Hold
Bit Status at Startup
(Programming Con-
sole address:
Word 80, bit 14)
Clear
(OFF)
At power ON: Clear
At mode change: Clear
At power ON: Clear
At mode change: Hold
Hold
(ON)
At power ON: Hold
At mode change: Hold
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