The
monitoring
function
of a peripheral cannot confirm the status
of
each device
all
the
time. The status latch function transfers and
saves the
device
data to
the
status latch area when the SLT
instruction is executed
in
the sequence program.
The
device data saved using the SLT instruction can be read by the
GPPPHPMGP
to
monitor
it.
(1
)
Application
The status latch function
can
be
used to check the device data
when
a
fault condition exists during debugging.
It
is also used to find causes when
a
fault condition exists
during sequence program execution by making
a
program that
will execute the SLT instruction if such a condition exists.
I
d
l
(2)
Processing
(a)
The following data is stored in the status latch area when
the SLT instruction is executed.
X,
Y,
M,
L,
S,
F,
B
-99
ON/OFF data
T,
C
.....................
Contact and coil
OWOFF
memory data and present value
D,
W,
A,
2,
V
*-99..9..
Stored data
(b)
Data is stored to the status
latch
area when the SLT
instruction is executed.
With devices which turn
onloff
or store data using
the
same condition, the data to
be
stored
in
the status latch
area differs before and after
the
execution
of
the SLT
instruction.
7
1
4
.7
d
!
J
.-
a
d
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