Mitsubishi Electric MELSEC iQ-R Series User Manual page 108

When the transmission control is performed with "Send data" set to "Enable" and "Receive data" set to
"Enable", C24 performs message transmission and message reception processing as described below.
(Page 239 Control Contents of DC Code Control)
During message transmission processing, time check by timer 1 (response monitoring time) is performed.
● Message transmission (-1 in the figure)
• When C24 receives a transmission terminate request (receiving DC3/DR(DSR) signal OFF) from the target
device during message transmission, C24 terminates data transmission.
• When the C24 receives a reception available signal (receiving DC1/DR(DSR) signal ON), C24 restarts data
transmission.
● Message reception
• If C24 cannot send a response message to the target device in response to message reception because the
target device issued a transmission terminate request (receiving DC3/DR(DSR) signal OFF), C24 transmits
the response message after it's in the data transmission available state (receiving DC1/DR(DSR) signal
ON).
4 DATA COMMUNICATION USING BIDIRECTIONAL PROTOCOL
106
4.3 Processing when Simultaneous Transmission is Performed during Full-Duplex Communications