4. A2CCPU
--------------------
MELSEC-A
I
•
4.2.7
Offline switch function
While
the
A2CCPU is running (sequence program being executed), it is
possible to turn the sequence program OUT instruction devices on and off
with a peripheral device test function.
The offline switch function allows these devices to be turned on and off while
the
A2CCPU is running with a peripheral device as the test function.
It is possible to check operation of OUT instruction devices, which are
not
turned on/off by the sequence program,
and
to check
the
wiring between
the
output module and an external device with the offline switch function.
Offline switch closed
OUT
instruction
......
Online state
.1
f-------------<c:)()
.....Offline state
.2
~
Offline
switch
opened
.'
: The online state is established when the offline switch is closed. The
OUT
instruction device is controlled (turned on/off) by the sequence program.
*2
: The offline state is established when the offline switch is opened.
The
OUT
instruction is isolated from the sequence program. In the offline state, it is not
possible to control the
OUT
devices by the sequence program.
Fig. 4.21
Offline
and
Online
State
(1) Devices which can be used by the offline switch function
The devices which can be used by the offline switch function are
indicated
below:
(a) Outputs
(V)
(b) Internal relays (M)
(c) Latch relays (L)
(d) Step relays (S)
(e) Link relays (B)
(f) Annunciators (F)
4-33
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