Changing The Communication Method; Connector Connections For Half-Duplex Communications - Mitsubishi Electric MELSEC iQ-R Series User Manual

12.3

Changing the Communication Method

To change the data communication method from full-duplex communication to half-duplex communication, setting the
following parameters is required.
Navigation window  [Parameter]  [Module Information]  "Module Name"  [Module Parameter]  "Basic Settings"
 "Various control specification"
RS-232 communication method designation
Set to "half-duplex communications".
Simultaneous transmission priority/non-priority designation
Set whether to continue ("priority") or stop ("non-priority") transmission from C24 when C24 and the target device start data
transmission simultaneously in half-duplex communications.
Setting values "1" to "255" to set to "Non-priority" will be the transmission wait time that elapses from when the resumption of
data transmission becomes available until data is actually sent.
Retransmission time transmission method designation
When "half-duplex communication" and "non-priority" are set as indicated above, this setting becomes valid. Set whether the
terminated message will be transmitted from the beginning ('Resend') or from the terminated part of the message ('Do not
resend') when C24 and the target device start transmission simultaneously, and C24 stops and then restarts transmitting.
RS-232 CD terminal check designation
Set the CD terminal check designation to "Check".
12.4
Connector Connections for Half-duplex
Communications
The following explains the connector that connects C24 and target device when half-duplex communications are used.
Connect to the target device in accordance with the following.
• Connect the C24 RS (RTS) signal to one of the target device signals (CS (CTS), DR (DSR), or CD (DCD) signal) for half-
duplex communications.
• Connect the C24 CD (DCD) signal to one of the target device signals (RS (RTS) or DR (DSR) signal) for half-duplex
communications.
• The half-duplex communications cannot be performed when an RS-232 and RS-422 converter is used.
C24
Signal name
CD(DCD)
RD(RXD)
SD(TXD)
ER(DTR)
SG
DR(DSR)
RS(RTS)
CS(CTS)
CI(RI)
12 DATA COMMUNICATIONS USING HALF-DUPLEX COMMUNICATIONS
248
12.3 Changing the Communication Method
Cable connection and signal direction
Pin No.
1
2
3
4
5
6
7
8
9
Target device
Signal name
CD(DCD)
RD(RXD)
SD(TXD)
ER(DTR)
SG
DR(DSR)
RS(RTS)
CS(CTS)