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Rev. 1.0

11/08/2017

STF-R/C Hardware Manual

400-820-9661

RS-485 network connection

Multiple –R model drive network can be built via dual RS-485 communication port by network

cable provided.

RS-485 Four-wire Conﬁguration

RS-485 four-wire system utilize separate transmit and receive wires. One pair of wires connect

the host’s transmit signals(TX+/TX-) to each drive’s RX+/RX- receive terminals. The other pair

connects the drive’s TX+/TX- terminals to the host’s receive signals. A logical ground terminal is

provided on each drive and can be used to keep all the drives at the same ground potential. The

rst drive’s logical GND of the RS-485 bus must connect to host’s ground.

Four-wire Connection

Connect the drive’s RX+ to the TX+ terminal of the host controller,and connect the drive’s RX- to

the TX- terminal of the host controller . Connect the drive’s TX+ to the RX+ terminal of the host

controller,and connect the drive’s TX- to the RX- terminal of the host controller .

Connect the drive’s GND and the host’s GND to a same ground.

NOTE: The RS-485 port on the drive is isolated from internal circuitry of the drive. So the

GND of each drive’s RS-485 port must be connected together. The rst drive’s GND of the

RS-485 port must be connected to the GND of RS-485 port on the host PC or controller.

RS-485 Tow-wire Conﬁguration

In a two-wire system ,the data transmitting and receiving use a same cable. the host must stop

its transmitting before receiving data. That means the host must stop transmit data before drive

begins to answer a query which just come from the host, otherwise the host cannot receive

any data witch sent from a drive. There is a transmit delay parameter that can be adjusted to

compensate for a host that is slow to disable its transmitter. This adjustment can be set over the

network using the TD command,it also can be set by using the STF Congurator software. Users

can set a shorter transmit delay in a four-wire system.

Two-wire connection

The RX+ and TX+ of the drive connect to the host’s + in parallel. The RX- and TX- of the drive

connect to the host’s - in parallel. Connect the drive’s GND and the host’s GND to a same ground.

NOTE: The RS-485 port on the drive is isolated from internal circuitry of the drive. So the

GND of each drive’s RS-485 port must be connected together. The rst drive’s GND of the

RS-485 port must be connected to the GND of RS-485 port on the host PC or controller.

Moons' STF-C Series User Manual

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