Mitsubishi MELSEC LJ71C24, User Manual

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6 SETTING AND WIRING
6.2.3 Connecting the RS-232 interface (full-duplex communication)
The following shows the connection precautions and connection examples when using
the C24 RS-232 interface for full-duplex communication.
(1) Connection precautions
(a) Refer to Appendix 11 for the bend radius of the connection cable.
(b) Do not install the control lines or communication cables together with the
main circuit lines or power cables.
Keep a distance of 100mm between them.
Failure to do so may result in malfunction due to noise.
(c) Connect the external device according to its specifications.
(d) Ground the shield at only one point.
(e) Connect the FG signal wire and shield as follows.
Connection on the C24 side Notes
FG signal Connect to the C24 connector housing
Shield
Connect to the FG terminal of the external
device or the C24 connector housing
Do not short the FG and SG signal wires of
the cable.
When the FG and SG signal wires are
connected inside the external device, do not
connect the FG signal to the C24.
(f) 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 C24 using the
shield of the connection cable.
2) Signals other than SG must be connected to the SG signals with the
twisted pair cables.