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8.
COMMUNICATIONS USING DEDICATED PROTOCOLS
MELSECA
8.14.2
On-Demand function control procedure
(1)
PC CPU control procedure
On-demand data
transmission
Check (and
if
necessary change) the contents of buffer
. .
. . . . .
memory address 103H. See Examples 1 and 2 in Seu
tion 8.14.3for transmission data formats when word or
byte units are selected.
Wriie to buffer memory address OH to FFH
or
120H to
7FFH (' 1 )
Clear the on-demand buffer memory address 10CH.
(Start is disabled
i f
the contents of this address are "Im.)
W r i i the head address where the data is stored to buff.
Start on-demand
........
er memory address 109H and the data length to ad-
dress IOAH.
H
"1'
is
wrmen to b d e r memory address IOCH, an
Transm:ssion crror check
........
error o c c ~ r s and the data is not transmnied
I
LC
Error
I
No error
*I
1
li
data communications is executed at the same time in
either the no-protocol mode or the bidirectional mode.
the area must not overlap with the following
area.
Transmission completed
0
No-protocol send area (bidirectional send area)
N ~ p r o t o c o l receive area (bidirectional receive area)
(2) Computer control procedure
On-demand data receive
+
Determine if the received data
The AJ71 C24 appends
'FE'
as the PC CPU number.
was received due to on-
........
Process data as on-demand data only if the PC CPU
demand function or command
number of the received data is FE.
Set transmission data
Receive completed
h
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