User`s manual

214
(b) When Q series C24 is designated "non-priority"
The contents of steps 4 and 5 below are different from those of Page 213, Section 8.2 (1) (a).
1) If the RS (RTS) signal is OFF, turn ON the CD (DCD) signal. If the RS (RTS) signal is ON, wait until it is
turned OFF, then turn ON the CD (DCD) signal.
2) Transmit data after turning ON the CD (DCD) signal.
3) After data transmission is complete, turn off the CD (DCD) signal.
4) Keep transmitting data from the external device to the Q series C24 even if the RS (RTS) signal is turned ON
during data transmission. (Simultaneous transmission generated)
5) After transmission from the external device is complete, data is transmitted from the Q series C24 to the
external device. ( Page 215, Section 8.2 (2))
*1 For transmission data, see Page 215, Section 8.2 (2).
Remark
When using the DTR/DSR transmission control function described in Page 203, CHAPTER 7, transmit data from the
external device to the Q series C24 as shown below in both cases Page 213, Section 8.2 (1) (a) and Page 214, Section 8.2
(1) (b).
• When the Q series C24 ER (DTR) signal is turned OFF, terminate data transmission.
• When the Q series C24 ER (DTR) signal is turned ON after data transmission is terminated, restart data
transmission (transmit from the terminated data).
1)
2)
3)
4)
5)
*1
External device
Programmable
controller CPU
SD(TXD) (Send Data)
RS(RTS)
(Send Request)
CS(CTS)
(Send Possible)
CD(DCD)
(Data Carrier Detect)
RD(RXD)
(Receive Data)
Data A
The Q series C24 stores
the receive data.
Data B
Data C-2
Data A
Data C-2
Continue data
transmission.
Retransmission
Data B
Data C-1
Data C-1
Since the Q series C24
does not have priority,
when the CD(DCD) signal
is turned ON, it terminates
transmission.