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SV200 DC Hardware Manual
920-0126A
4/14/2017
9.2.2 RS-485 Connection Method
RS-422/485 communication allows connection of more than one drive to a single host PC, PLC, HMI or other computer. It also allows
the communication cable to be long. The use of Category 5 cable is recommended as it is widely used for computer networks, is
inexpensive, easily obtained and certified for quality and data integrity.
The SV200 drives can be used with either Two-Wire or Four-Wire RS-422/485 implementation. The connection can be point-to-point
(i.e. one drive and one host) or a multi-drop network (one host and up to 32 drives).
Four-Wire Configuration
Four-wire systems utilize separate transmit and receive wires. One pair of wires must connect the host’s transmit signals to each drive’s
RX+ and RX- terminals. The other pair connects the drive’s TX+ and TX- terminals to the host’s receive signals. A logic ground terminal
is provided on each drive and can be used to keep all drives at the same ground potential. This terminal connects internally to the
DC power supply return (V-), so if all the drives on the RS-422/485 network are powered from the same supply it is not necessary to
connect the logic grounds. One drive’s GND terminal should still be connected to the host computer ground.
Two-Wire Configuration
In a 2-wire system, the host must disable its transmitter before it can receive data. This must be done quickly before a drive begins
to answer a query. The SV200 drives include a transmit delay parameter that can be adjusted to compensate for a host that is slow to
disable its transmitter. This adjustment can be made over the network using the TD command, or it can be set using the SVX Servo
Suite software. It is not necessary to set the transmit delay in a four wire system.
NOTE: For RJ45 crystal connector, we recommend standard CAT5 cables.
