Mitsubishi MELSEC LJ71C24, User Manual

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6 SETTING AND WIRING
(g) Terminating resistors must be set (or connected) for both terminal stations
on the line.
On the C24 side, connect the terminating resistor (included with the C24)
according to the specifications of the external device.
On the external device side, connect, or set a terminating resistor according
to the instruction manual of the external device.
(C24-side terminal resistor)
• For RS-422 communications, connect the terminating resistor of "330
1/4 W".
• For RS-485 communications, connect the terminating resistor of "110
1/2 W".
Differences between these terminating resistors
330
Ω
110
Ω
Brown
Orange Orange
Brown Brown Brown
Gold
Gold
(h) If data cannot be communicated with the external device at all, check the
polarity of the external device. If the polarities of the C24 and the external
device do not match, reverse the polarity of each signal on either device side
and connect the devices with the cable so that the data may be
communicated.
(i) Unify the connection of devices to the RS-422/485 interface of C24 (including
the 1:n, n:1 and m:n connections ) to either RS-422 or RS-485.