3.2.2. CONNECTION TO 4-WIRE RS485 BUS
Fig. 4. Example connection of RS485(4W) devices.
3.2.3. CONNECTION TO 2-WIRE RS485 BUS
Most of RS485 devices use 2-wire RS485 network for data transmission, example of connection ADA-7240 to 2-wire RS485 network is
shown below.
Fig. 5. Example connection of RS485(2W) devices.
3.2.4. LINE TERMINATION Rt ON RS485/RS422 BUS.
The application of Line Termination (terminator) Rt = 120
W
will reduce electrical reflection in data line at high baud rate. It is not
needed below 9600Bd should be used the Line Termination resistor if the distance is over 1000m @ 9600Bd or 700m @ 19200Bd
transmission. Example connection of Rt are shown on Fig. 3, 4 & 5. Two resistors Rt =120
W
, are supplied with ADA-7240 converter,
free of charge.
6
ADA-7240
RS485(4W) bus
TX2
RX2
TX1
RX1
FO
connector
Rt
RX+
RX-
GND
TX+ / A
TX- / B
V +
V -
V -
V +
RS485(4W)
connector
Power Supply
ADA-7240
Rt
Multimode optical
fibers type:
50/125um,
62,5/125 um,
100/140um,
200umHCS,
Plastics
POF/1mm,
RS485(2W) bus
TX2
RX2
TX1
RX1
RX+
RX-
GND
TX+ / A
TX- / B
V +
V -
V -
V +
ADA-7240
Rt
FO
connector
RS485(2W)
connector
Power Supply
Multimode optical
fibers type:
50/125um,
62,5/125 um,
100/140um,
200umHCS,
Plastics
POF/1mm,
