Mitsubishi Electric FX3U-232-BD User Manual page 624

FX Series PLC User's Manual - Data Communication Edition
Non-Protocol Communication (RS/RS2 Instruction)
4. When the control line is in the interlink mode
RS2
instruction
OFF ON
driving
SD (TXD)
Send data
Sending
request
M8402
DR (DSR)
RD (RXD)
Receive data
Time-out
check
flag M8409
Receiving
complete
M8403
ER (DTR)
*1. On the external equipment side, set the DR (DSR) signal to ON when the external equipment is ready
to receive.
The FX
3S
and the sending request turn ON.
*2. In the interlink mode, the PLC sets ER (DTR) to OFF when the amount of data already received
becomes "Number of bytes to be received -30", and asks the external equipment to stop sending.
After that, the PLC can only receive up to 30 characters. In this case, temporarily stop sending, and
then send the remaining data after the ER (DTR) signal turns ON again.
When sending is stopped, the PLC finishes receiving after the time-out time setting is reached.
When sending is not stopped, the PLC finishes receiving after it has received the final send data or 30
characters. Accordingly, make sure that the number of receive characters are "30 + ".
F-74
Message
2
ON
OFF ON
*1
Message
1
OFF ON
ON OFF
, FX , FX , FX and FX
3G 3GC 3U
Message
4
OFF
*1
Up to 30 characters can be
received.
Message 3
Time-out
time setting
D8409  10 ms
Reset it in a sequence program.
While it remains ON, the PLC cannot receive the next set of data.
PLCs sends the send data when both the DR (DSR) signal
3UC
8 Creating Programs (RS2 Instruction)
8.3 Operation of Control Line
Message
4
*1
*2
Message
3
ON ON