User`s manual

FX communication
RS instruction 9
9-10
9.2.2 FX
2N
, FX
2NC
(V 2.00 or later)
In the FX
2N
V 2.00 or later, full duplex communication is performed. When performing half duplex
communication, pay rigid attention so that the send flag is not turned on while data is received. If
it is turned on, send is started. As the result, the counterpart equipment may not be able to
receive data or the send/receive data may be damaged.
In full duplex communication, the send wait flag M8121 is not turned on.
In version V 2.00 or later, the programming protocol (Section 12) is supported while an RS
instruction remains OFF.
1 ) Do not use hardware hand shake
2 ) Use terminal mode of control line
This mode is available for send only or receive only.
The control line and the transmission sequence are equivalent to those in the FX
2N
series
whose version is earlier than V 2.00. Refer to paragraph 9.2.1.
Reset using a program.
When it is not trurned off, the next
data cannot be received.
Data 1
RS instruction
driving
Send data
SD (TXD)
OFF ON
Data 5
OFF ON
Send request
M8122
Receive
completion
M8123
Data 3
Data 2
Data 4
OFF ON ON
The receive wait
status is started
Receive data
RD (RXD)