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10. COMMUNICATIONS IN THE BIDIRECTIONAL MODE
MELSEC-A
10.6
Processlng an AJ71C24 for Slmultaneous Send In Full-Duplex Mode
Processing by the
AJ71C24
varies depending on the setting
(validlinvaiid
setting at simultaneous transmission) when
the
computer and the
AJ71 C24
transmit data at the same time to each other.
Example:
Computer
Buffer
Memory Setting
(Address 11 4H)
O O O O H
OlOIH
Setting
Send data
: Valid
Received data
: Valid
Send data
: invalid
Received data
: Valid
Send data
: Valid
Received data
: Invalid
Send data
: Invalid
Received data
: invalid
Processing by AJ71C24
Send Processing
After completing data send ((1)-
I ) . the AJ71C24 waits for
response ((1)-2) while checking
time-out error.
Normal or abnormal send com-
pletion is confirmed by response
and its status is transmitted to the
sequence program via the buffer
memory.
After completing data send ((1)-
I), theAJ71-4
transmits the se-
quence
program
of
a
simutlaneous transmission error
(error code: 3) via the buffer
mernow.
The
A J ? ~
~ 2 4
does not wait for a
response ((1)-2).
After completing data send ((1)-
I ) , the AJ71C24 waits for a
response ((1)-2) while checking
time-out error.
Normal or abnormal send com-
pletion is confirmed b y a
resDonse and its status is trans-
mitted to the sequence program
via the buffer memory.
After completing data send ((1)-
1). the AJ71C24 transmits the se-
q u e n c e
program
of
a
simultaneous transmission error
(error code: 3) via the buffer
memory.
The AJ71C24 does not wait for a
response ((1)-2).
Receive Processing
After comDletina data receive
((2)-l),the~~71~>4transmitsthe
response ((2)-2).
The received data and receive
result are transmitted to the se-
quence program via the buffer
memory
After completing data receive
((2)-I), theAJ7IC24transmitsthe
response ((2)-2).
The receive data and receive
resutl are transmitted to the
se-
quence program via the buffer
memory.
Data receive ((2)-1) is ignored
and received data is discarded.
The response ((2)-2 is not trans-
mitted.
Data receive is not transmitted to
the sequence program.
Data receive ((2)-I) is ignored
and received data is discarded.
The response ((2)-2 is not trans-
mitted.
Data receive is not transmitted to
the sequence program.
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