Mitsubishi Electric MELSEC FX Series User Manual page 114

FX communication
4 ) Use interlink mode of control line
RS instruction
driving
Send data
SD (TXD)
Send request
M8122
DR(DSR)
Receive data
RD (RXD)
Time-out
evaluation
flag M8129
Receive
completion
M8123
ER(DTR)
*1 While the counterpart equipment is ready to receive, turn ON the DR (DSR) signal.
While both the DR (DSR) signal and the send request are turned on, the FX
*2 In the interlink mode, the programmable controller turns OFF the ER (DTR) signal before the
30th character receive buffer limit, and requests the counterpart equipment to stop send.
After this send request, up to 30 characters can be received. The 31st and later characters
cannot be received. Stop send temporarily, then send the remaining data after the ER (DTR)
signal is turned ON again.
When send is stopped, receive is completed after the time-out evaluation time is expired.
When send is not stopped, receive is completed after the final character of the send data is
received or the 30th character is received. Therefore, receive points need to set 30th or more.
*3 Reset using a sequence program.
If it is turned ON, the next data cannot be received.
In the interlink mode, make sure to set the number of receive points to 30 characters or more.
OFF ON
Data 2
ON
OFF
*1
Data 1
Reset it using a program.
When it is not trurned off,
the next data cannot be
received.
OFF ON
ON OFF
OFF
ON
*1
Data 3
RS instruction 9
Data 4 Data 4
*1
Up to 30 characfers can be
received *2
Data 3
Time-out
evaluation time
D8129×10ms
*3
ON
Reset using a program.
When it is not trurned off, the
next data cannot be received.
sends the data.
2N
ON
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