Table of Contents
Advertisement
3. SPECIFICATIONS
MELSEC-A
(1) The functions available with the no-protocol mode cannot be used
together with the functions available with the bidirectional mode men-
tioned in Section 3.3.1.(3). Select either mode using the mode setting
switch (see Section 4.3.1) and by setting the bidirectional mode setting
area in the special applications buffer memory area (see Sections 3.5
and 10.2).
(2)
The receive-completed code and the receive-completion data length
can be set and enabled at the same time. When both of them are
enabled, the received data read request to the sequence program is
made in response to whichever is received first by the AlSJ71C24.
(3)
Functions available in the bidirectional mode
(a) Functions in the bidirectional mode
\
Send (PC
CPU
-
computer)
Receive
(Computer
-
PC
CPU)
Number of
Points
Processed per
Communications
-
-
A PC CPU uses the TO instruction to
output data written to the A1 SJ71 CZ4
buffer memory area in unchanged
code to a computer.
-
When the AlSJ71 C24 receives the
response message from a computer
after data send the AlSJ71 C24
transmits a send completed signal to
the sequence program.
A PC CPU uses the FROM instruction
to read data from the AlSJ71 C24
buffer memory which was transmitted
by a computer.
-
When the AlSJ71C24 receives the
data read completed signal from the
sequence program, the AlSJ71 C24
transmits a response message for the
data receive to a computer.
127 words
(default value).
Can be changed
with the buffer
size setting
(see
Sections
7.4.4 and 7.4.5.)
PC CPU State
luring
STOP
u r l n g RUN
Reference
Section
Section 10
(b) Setting data length setting for data send
The length of the data to be transmitted between an AlSJ71 C24 and
a computer is set within the send message. (see Section 1.1.1 (2)
(b)).
1) When data is transmitted to a computer:
When the data to be transmitted to a computer is output from the
sequence program to an AlSJ71 C24, the data length is written to
the buffer memory of the AlSJ71C24.
The AlSJ71C24 sets the data length to a send message and
transmits it along with the data to a computer.
This allows the length of a send message to vary according to the
content and kind of data to be transmitted.
Advertisement
Table of Contents
