F-72
FX Series PLC User's Manual - Data Communication Edition
Non-Protocol Communication (RS/RS2 Instruction)
8 Creating Programs (RS2 Instruction)
8.3 Operation of Control Line
8.3
Operation of Control Line
FX
3S
, FX
3G
, FX
3GC
, FX
3U
and FX
3UC
PLCs execute full-duplex, bidirectional communication. When
executing half-duplex, bidirectional communication, pay attention not to set the sending request to ON while
receiving. If the sending request is set to ON, the PLC starts to send. As a result, the external equipment may
not be able to receive data, and the sent and received data may be destroyed.
In full-duplex, bidirectional communication, the sending wait flag M8371, M8401, and M8421 does not turn
ON.
However, the sending wait flag M8371, M8401, and M8421 remains ON while the DR (DSR) is OFF, the PLC
waits to send, and the control line is in the standard mode or interlink mode.
1. When the control line is not provided
Reset it in a sequence program.
While it remains ON, the PLC cannot receive the next
set of data.
OFF ON
OFF
ON
OFF
ON
ON
Receiving wait status
is started.
Message
1
Message
3
Message
5
Message 4
Message
2
RS2
instruction
driving
SD (TXD)
Send data
Sending
request
M8402
RD (RXD)
Receive data
Receiving
complete
M8403
Summary of Contents for FX-485ADP
Page 2: ......
Page 120: ...B 2 FX Series PLC User s Manual Data Communication Edition N N Network ...
Page 188: ...C 2 FX Series PLC User s Manual Data Communication Edition Parallel Link ...
Page 244: ...D 2 FX Series PLC User s Manual Data Communication Edition Computer Link ...
Page 344: ...E 2 FX Series PLC User s Manual Data Communication Edition Inverter Communication ...
Page 700: ...H 2 FX Series PLC User s Manual Data Communication Edition Programming Communication ...
Page 752: ...I 2 FX Series PLC User s Manual Data Communication Edition Remote Maintenance ...
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