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3.
SPECIFICATIONS
MELSEC-A
(2)
Functions available in the no-protocol mode
(a) Functions in the no-protocol mode
0
There are two ways to complete the data receive when an
AlSJ71C24 is receiving data from an external device:
1) Reading the received data using the receive completed code
(receive of variable-length data)
Com-
mand
When an AlSJ71C24 receives the receive completed code which
is set in the buffer memory by the user from an external device,
the AlSJ71C24 transmits a received data read request to the
sequence program.
(b) Receive completion by the completed code and by the completion
data length
Description
A PC CPU uses the TO instruction to
output data written to an AlSJ71C24
buffer memory area in unchanged
code to an external device.
A
PC CPU uses the FROM instruction
to read from an AlSJ71C24 buffer
memory which was transmitted from
an external device.
Send
(PCCPU
-
external
device)
Receive
(External
device
-
PC CPU)
The sequence program, in response to the read request, reads
the received data up to the receive completed code transmitted
by the external device.
-
-
The user can freely set the receive completed code.
Number o f
Points
Processed per
Communications
127 words
(default value).
Can bechanged
with buffer size
setting
(see Sections
7.4.4 and 7.4.5.).
2) Reading the received data using the receive-completion data
length (receive of fixed-length data)
When an AlSJ71C24 receives data of a designated length which
is set in the buffer memory by the user from an external device,
the AlSJ71C24 transmits a received data read request to the
sequence program.
The sequence program, in response to the read request, reads
the received data of the designated length transmitted by the
external device.
Reference
Section
Seclion9
PC CPU State
The receive-completion data length can be set within the buffer
memory area allocated for the no-protocol receive.
nuring
STOP
o
During RUN
SW04
ON
o
SW04
OFF
o
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