Rs485(2W) Bus Connection; Gnd Terminals Connection; Line Termination Rt; Slave Device Connection - CEL-MAR ADA-4040PC1 User Manual

ADA-4040PC1

3.3.2. RS485(2W) BUS CONNECTION

MODBUS-ASCII / MODBUS-RTU
RS485 / RS422
RS485/RS422
connector
Tx+/ A Tx+/ A
Rt Rt
Tx-/ B Tx-/ B
Rx+ Rx+ Tx+/ A Tx+/ A
Rt Rt
Rx- Rx- Tx-/ B Tx-/ B
GND GND
MASTER
MODBUS-ASCII
DEVICE
Fig 7. Example connection of ADA-4040PC1 to RS485(2W) 2-wire bus and galvanic separation of SLAVE device

3.3.3. GND TERMINALS CONNECTION

Connection of GND terminals of RS485/422 interfaces, devices connected to RS485/422 bus, should be done in the case of a
potential difference of the signals grounds on interfaces RS485 / RS422, which prevents proper data transmission.
Cannot connect to the GND terminal - cables screens, PE circuit of electrical installation, signals grounds of other devices.

3.3.4. LINE TERMINATION Rt

The application of Line Termination (terminator) Rt = 120 ohms 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,
and if the disturbance in transmission will appear.
Example connection of Rt are shown on Fig. 6 & 7. Four Rt=120 W , 5%, 0,25W are delivered with the converters.

3.3.5. SLAVE DEVICE CONNECTION

Connection of SLAVE devices to ADA-4040PC1 are shown on fig. 5 and fig. 6.

3.4. POWER SUPPLY CONNECTION

To connect power supply to the converter, should have DC power supplies (regulated) output voltage from 10 V= to 30V=, min.
nominal power 2W, e.g. ZS-12/250. Power cable from DC power supplies to device can not be longer than 3m. Should connect
positive (+) end of DC power supplies to V+ device terminal and negative (-) end to V- on terminal block. ADA-4040PC1 has protection
against power supply reverse connection.

4. ACIVATION

The converter Can be power on after properly connection according to section above.
If after connection power supply on front panel will not light green led PWR, check correctness of power supply connecting
(polarization). When data is present the LEDs Tx and Rx should blink
ADA-4040PC1
ASCII RTU
RS485/RS422
connector connector
Rx+ Rx+ Tx+/ A Tx+/ A
Rt Rt
Rt
Rx- Rx- Tx-/ B Tx-/ B
Rx+ Rx+
Rt Rt
Rt
Rx- Rx-
GND GND GND
RS485 (2W) bus
9600Bd/8/N/1
MODBUS-RTU
SLAVE-1
MODBUS-RTU
7
SLAVE-2
MODBUS-RTU
RS485(2W)
19200/Bd/7/N/2
SLAVE-3
MODBUS-ASCII