Table of Contents
Advertisement
APPENDICES
MELSEC-A
When DC1 is received, until the following DC3 is received, received D C l
is processed as data.
When DC3 is received, until the following DC1 is received, received DC3
is processed as data.
When received data cannot be stored in an OS receive area, that
received data is ignored until the following received data is stored.
DCllDC3 receive control can only be done using full-duplex communica-
tions.
When the power supply is turned ON or the PC CPU is reset, DC1 is not
received form the external device.
The state is the same as when DC1 was received.
4.4
DC2lDC4 Receive Control
D
External device
C
3
DC2lDC4 receive control is discussed below.
D
C
1
A1 a 7 1 C24
When an AlSJ71C24 receives data from the external device, the
AlSJ71C24 stores the following data in an AlSJ71C24 buffer or a
receive area for OS as valid data.
The data is data supplemented by DC2 and DC4.
In this case, the user cannot access the received DC2lDC4.
Data
Data
When DC2 is received, until DC4 is received, received DC2 is processed
as data.
When DC4 is received, until DC2 is received, all received data is
disregarded as invalid data.
DC2 and DC4 cannot be included in user data which is transmitted from
an external device to the AlSJ71C24.
When it is necessary to include DC2 and DC4, do not do receive control
of DC2lDC4.
A1 SJ71 C24
.
d
.
/
Stored in the
I
The A1 SJ71 C24
Stored in the
A1 9 7 1 C24 buffer
or
ignores this data.
A1 5171 C24 buffer or
the
OS
receive
area
the
OS receive area.
External device
APP
-
6
D
C
2
Any data
t
Data
D
C
4
D
C
2
Data
D
C
4
Advertisement
Table of Contents
