Connecting The Rs-232 Interface (Full-Duplex Communications) - Mitsubishi QJ71C24N User Manual

4 SETTINGS AND PROCEDURES PRIOR TO OPERATION

4.4.1 Connecting the RS-232 interface (full-duplex communications)

Connection cable FG signal
Connection cable shield
4 - 6
The following shows the connection precautions and connection examples when using
the Q series C24 RS-232 interface for full-duplex communications.
(1) Connection precautions
(a) For further information about the following items, see the explanation in the
applicable section in the User's Manual (Application).
• Controlling the communication on the Q series C24 side by the external
device side using the CD(DCD) signal of the RS-232 interface.
This is affected by the "CD terminal check designation" in "CHn
transmission control and others system setting" screen on GX
Configurator-SC.
• Performing half-duplex communication using specifications on the external
device side (an example of such a connection is shown in this section).
• Using modem functions.
(b) The connection cable FG signal and shield are connected as follows.
Connection on the Q series C24 side
Connect to the Q series C24 connector
housing
Connect to the external device FG terminal
or the Q series C24 connector housing
(c) When normal data communication is not obtained due to external noise,
perform the wiring as follows:
1) Connect the FG terminals on the external device and the Q series C24
using the shield of the connection cable.
2) Signals other than SG should be connected with SG signals in the
twisted pair.
POINT
When using an RS-232 to RS-422 converter to connect the external device and the
Q series C24, use a converter that is compatible with the external device and
programmable controller CPU system configuration (1:1).
Notes
Do not short the communication cable FG
signal and the SG signal.
When the FG signal and the SG signal are
connected inside the external device, do not
connect the FG signal to the Q series C24.
MELSEC-Q
4 - 6