Rs-422/Rs-485 Interface - YASKAWA S-V Series User Manual

4 Wiring and Connection

4.3.5 RS-422/RS-485 Interface

4.3.5 RS-422/RS-485 Interface

The maximum total length for RS-422 or RS-485 cable is 50 m. Use the minimum length of cable that is
needed.
The INDEXER Module's communications circuits are not insulated. If communications errors occur because
of noise, use noise suppression methods such as shielded cable or ferrite cores.
When using full-duplex wiring, connect a terminator in the host controller's reception circuit and the reception
circuit of the last INDEXER Module in the line. The INDEXER Module has a built-in terminator (120 Ω) that
is connected between the RXD and /RXD pins when the RT and /RXD pins are shorted.
When using half-duplex wiring, connect a terminator at both ends of the communications cable. The
INDEXER Module has a built-in terminator (120 Ω) that is connected between the RXD and /RXD pins when
the RT and /RXD pins are shorted.
The INDEXER Module's transmission circuit is high-impedance when it is not transmitting. Pull-up or pull-
down the host controller's reception circuit.
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