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3. LINKING TO THE A2CCPU
MELSEC-A
3.5.3
Precautions when programming
(1)
It is necessary to provide the
PRC instruction to the step immediately
following the FROMDO instruction. Be careful
not to designate the
same devices for " m l " of the PRC instruction and for " m l " of the PRC
instruction provided to another step.
I
- - - -
FROM1
H5
I
K10
I
D l 0
I
K2
Do not designate
the same device
(ml)
number.
m2 is a dummy and has no
meaning.
(2) The request-to-communicate registration areas can store up to
32
FROMDO instructions. If the 33rd FROM/TO instruction is given, it
is
ignored (without processing) and an "OPERATION ERROR" will occur.
Provide an interlock with the M9081 and D9081
so that the FROM/TO
instruction will
not be executed when the request-to-communicate
registration areas are full.
M9081 and D9081 are described below.
No.
1
Descriptions
I
Details
OFF: A request-to-communicate
terminals. Goes
ON
when all
ON
:
The request-to-communicate
There are 32 request-to-communi-
M9081
registration area has a vacancy.
these areas are full.
registration areas are full.
cate registration areas for remote
The number of vacant areas in the
D9081
area for remote terminals.
request-to-communicate registration
The number of vacant areas in
the request-to-communicate
registration storage area.
When data is written to two
or more addresses
in the buffer of an
A64RDC, one FROM/TO instruction can execute data write if the addres-
ses are continuous. If the addresses are not continuous, it
is
necessary
to execute the FROM/TO instruction at two or more points (see below).
In this case, more than one FROM/TO piece of instruction information is
stored in the request-to-communicate registration areas.
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