4.A2CCPU
_-------------------
MELSEC-A
(1) Operation processing in RUN state
(a) The RUN state indicates the state in which
the
PC CPU operates a
sequence program repeatedly from
step
0 to
the
END (FEND) I
instruction.
(b) The
output
status of the
outputs
(V)
at
the
entry to
the
RUN state
varies according to the 'STOP
....
RUN
output"
mode
set with a
parameter.
1) Output of operation state before STOP
After
the
outputs (y) saved before the entry to
the
STOP state
are output,
the
PC CPU executes the sequence program.
2) Output after operation
Outputs
(Y) are
output
after one scan of
the
sequence program.
The time required before starting sequence program operation
after
the
changing
the
switch from STOP to RUN varies according t
to
the
system
configuration;
it is
usually
between 1
and
3
seconds.
(c) In the RUN state,
the
processing illustrated in Fig. 4.8 is repeated
until
the
operation state is changed from RUN to STOP or PAUSE.
RUN
)
Is the output
NO (After 1 scan)
mode at STOP-to-RUN
switch before
operation'?
YES (Before operation)
The
status of the outputs M
which have
been
saved
before entering the STOP
state is
set
to the
device
area.
I
I/O modules are refreshed
Sequence program operation
processing
Step 0
to
END (FEND) instruction
END
processing
I
I
Operation state check
I
•
Fig. 4.8 RUN
Operation
Processing
IREMARKSI
For details on individual processing in Fig. 4.8, refer to Section 4.1.1 to Section
4.1.3.
4-14
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