1. INTRODUCTION
--------------------
MELSEC·A
1.1 General
Description
of
Operation
This section describes the datacommunication between
the
A2C,
the
remote
I/O module and
the
remote terminal module.
See Section 4.2
for
the A2C functions.
1.1.1 ON/OFF data communication between the A2C and the remote I/O module
ON/OFF data communication is performed using inputs (X) and outputs
(Y).
(1) Input/output number assignment of
the
remote I/O module
The
input/output
numbers of the A2C system are assigned from x/yOOO
to X/y1 FF in
the
order of the station number
(1
to 64) set
for
each remote
I/O module.
Data communication with a remote I/O module is performed using ..
inputs (X) and outputs
(Y)
assigned
for
each module.
'Ill
See Section 4.7 for
the
relationship between station numbers and i/O
numbers.
(2) ON/OFF data communication with
the
remote I/O module
The ON/OFF data communication with the remote I/O module is per-
formed in the refresh mode.
Fig. 1.1 shows the data communication between the A2C and the
~
remote I/O modules. ,
(b)
ON/OFF
data
of
output
(Y) is
output.
I
A2C
Station:
1
(a) Sequence program execution
I
-:
CPU
I/O
H
X
?
/'
(c)
ON/OFF
data
from
the
o ,
Y20
input
(x)
module
Is taken in.
,
Station:
9
I/O
,
MINI-S3Iink
,
~_r,l
,
n '-'
Y21
~
I/O
0------
I/O
The sequence
program
uses
input
(X) and
output
M
numbers
to
control
remote
I/O
Station:
n
Station:
5
modules.
When
the
A2C is
running,
operations
(a), (b)
and
(0)
mentioned
below
are
executed
repeatedly.
(a) The sequence program is executed from
step
0 to END (FEND).
(b)
ON/OFF
data
of an
output
(Y) in
the
sequenca
program
is
output
by the MINI-S3 link.
(c)
ON/OFF
data
from
an
input
module
is
taken
In by
the
MINI-S3
link.
Fig. 1.1 ON/OFF Data
Communication
between
the
A2C and
the
Remote I/O
Modules
1-2
41
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