Fig 5. Connection to PC by the use of RS232 to RS485/422 converter ADA-I1040 – 2-wires RS485
3.3. CONNECTION TO RS485 BUS
RS485/422 interface at ADA-4021 converter is available on terminal block described as: Tx+/A, Tx-/B, Rx+, Rx-.
Types of connection the ADA-4021 converter to RS485(4W)/RS422 and RS485(2W) bus are shown below.
3.3.1. 4-WIRE CONNECTION
After connection devices according to figure below, the converter should be set for operating on RS485 bus – see pt. 4.1.
Fig 6. Example connection to RS485 4-wires bus
3.3.2. 2-WIRE CONNECTION
After connection devices according to figure below, the converter should be set for operating on RS485 bus – see pt. 4.1.
Fig 7. Example connection to RS485 2-wires bus
3.3.3. LINE TERMINATION
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. 6 & 7. Two resistors Rt =120
W
, 5%, 0,25W are supplied with ADA-4021
converter, free of charge.
6
ADA-4021
(5) GND
GND
(2) Rx
(3) Tx
RS232
DB-9F/DCE
RS485/422
connector
RS485(4W) bus
RS232
DB-9M/DTE
PC or
MASTER device
ADA-I1040
GND (5)
Tx (2)
Rx (3)
Rt
Rt
Rx+
Rx-
Tx+/ A
Tx-/ B
(5) GND
GND
(2) Rx
(3) Tx
RS485(2W)
PC
ADA-I1040
GND (5)
Tx (2)
Rx (3)
Rx+
Rx-
Tx+/ A
Tx-/ B
Tx+ / A
Tx- / B
Rx+
Rx-
GND
ADA-4021
RS232
DB-9F/DCE
RS485/422
connector
RS232
DB-9M/DTE
RS485/422
connector
(5) GND
GND
(2) Rx
(3) Tx
RS232
DB-9F/DCE
RS232
DB-9M/DTE
ADA-I1040
GND (5)
Tx (2)
Rx (3)
Rt
Rx+
Rx-
Tx+/ A
Tx-/ B
RS485(2W) bus
PC or
MASTER device
RS485/422
connector
Summary of Contents for ADA-4021
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