User manual

53
Allowed Functions in Operation Modes
5
=On, ◑ =Flashing,
●
=Off
When the PROG.LED is on, you can change the user program.
The INITIALIZE switch clears errors when the mode switch is set to
PROG.
When the mode switch is set to REMOTE and power is switched from
Off to On, the previous mode of operation is restored.
When debugging the user program, the mode switch should be set to
REMOTE.
Processor Processing Procedure
Program processing procedure
• Program analysis
Executes the program from its first step to its final step and stores
the internal/external output in the working RAM.
• Peripheral device signal processing
Stores data from the communication module or peripheral device
to the internal memory.
• Forced I/O processing
Turns on/off forced I/O bits, if any.
• I/O processing
Preserves the On/Off state of the external I/O and uses it as an
input in the next scan. (For accurate processing, input should
continue for more than 1 scan time.)
The processed program outputs are sent from internal memory to
the external memory.
Operation mode
selector switch
Operation
mode
LED status
RUN LED
PROG LED
Program
change
Data
change
Initialize
switch is
enabled
Mode at power
off-on
RUN
RUN
5
●
Disallowed Allowed
○
Run
STOP
●
5
Allowed Allowed
○
Run
REMOTE
RUN
5 5
Allowed Allowed
○
Run
PAUSE
◑
5
Allowed Allowed
○
Pause
PROG STOP
●
5
Allowed Allowed
○
Stop
Program
analysis
The diagram indicates the PLC
program processing procedure.
The CPU regularly repeats
procedure 1 through 5. This cycle
is called 1 scan time.
1 scan time
Peripheral device
signal processing
Forced I/O
Process I/O
Watchdog time -> 0