Mitsubishi Electric AJ71C24-S6 User Manual page 242

9.
COMMUNICATIONS IN THE NO-PROTOCOL MODE
MELSEC-A
If the receive data length exceeds the no-protocol mode receive buffer memory size, the data
is processed as described below.
(1) When the receive completed code is used:
If the AJ71C24 receives data that exceeds the receive area size, it turns ON the received
data read request signal Xnl when date equivalent to the receive area size has been
received.
Reading the remaining data is enabled at the time the sequence program turns the receive
data read completed signal Y ( n + l ) l ON.
These steps are repeated until the receive completed code is received
Set the receive area size so that "receive-completion data length" is less than "no-protocol
mode receive buffer memory size".
Example: To receive 150 words of data while receive area is set at 80H to FFH (default).
r
Read completed code
127 words
23
words
External device
\
\
Received data read request
Xnl
Received data read completed
Y(.+,)l
FROM instruotion
(Reads 127 words of data) (Read 23 words of data)
(2) When receive completion data length is used:
If the receive completion data length is set greater than the receive area size, the no-
protocol receive buffer memory size (default: 127 words) which is set at buffer memory
address 107H is taken as the receive completion data length.
Set the receive area size so that "receive completion data length" is less than "no-protocol
mode receive buffer memory size".
Example: To receive 150 words of data while receive area is set at 80H to FFH (default setting).
Data transmitted for the first time
Data transmitted for the second time
Data transmitted for the third time
Received
data read
request Xnl
Receive
data read
completed PC CPU program FROM instruction
FROM instruction FROM insbuction
Y(n+i)l
(Reads 127 words of data
(Read 23 words of the first
of the first transmission)
transmission, and 104 words of
the second transmissionl
External
device
)
\
127 words
23
words
104 words 81 words
46
words
69
words