User`s manual

216
(b) When Q series C24 is designated "non-priority"
The contents of steps 4 and 5 below are different from those of Page 215, Section 8.2 (2) (a).
1) When transmitting data, check the Q series C24 CD (DCD) signal. If the CD (DCD) signal is off, turn on the
Q series C24 RS (RTS) signal. If the CD (DCD) signal is ON, wait until it is turned OFF, then turn ON the RS
(RTS) signal.
2) Transmit the data after turning ON the RS (RTS) signal.
3) After data transmission is complete, turn off the RS (RTS) signal.
4) If the CD (DCD) signal is turned on during data transmission, terminate data transmission and turn off the RS
(RTS) signal and perform the data receive processing. (Simultaneous transmission generated)
5) After transmission from the external device is complete, transmit the data terminated at step 4 from the
beginning or from the last data transmitted.
*2
*1 The data size set to "Simultaneous transmission priority/non-priority" by GX Configurator-SC is not transmitted.
*2 Transmit from the beginning or from the data transmitted immediately before transmission was terminated, according to
the contents set to "Retransmission time transmission method by GX Configurator-SC".
Remark
When using the DTR/DSR transmission control function described in Page 203, CHAPTER 7, transmit data from the Q
series C24 to the external device as shown below in both cases Page 215, Section 8.2 (2) (a) and Page 216, Section 8.2 (2)
(b) above.
• When the Q series C24 DR (DSR) signal is turned OFF, terminate data transmission.
• When the Q series C24 DR (DSR) signal is turned on after data transmission is terminated, restart data
transmission (transmit from the terminated data).
1)
4)
5)
2)
3)
External device
Programmable
controller CPU
Data A
The Q series C24 stores the receive data.
Data C
Data B
Continue data transmission.
Data A
Send
request
CD check CD check
CD check
Data C
Data B
Data B
Transmission wait time
(*1)
Data B
CD check
(*2)
SD(TXD) (Send Data)
RS(RTS)
(Send Request)
CS(CTS)
(Send Possible)
CD(DCD)
(Data Carrier Detect)
RD(RXD)
(Receive Data)
Send
request
Time for
transmitting
2 characters
Since the Q series C24
does not have priority, when
the CD(DCD) signal is turned ON
it terminates transmission.