Cables Description; Link Configuration; 2-Wire Rs485 Example Of Wiring - ADEUNIS sigfox MODBUS MASTER Guide Utilisateur

sigfox MODBUS MASTER - Guide utilisateur / User guide version V2.0.0

4.3. Cables description

FR
Cable with 2-wire for supply
EN

4.4. Link configuration

The Modbus physical layer supports a RS485 (default) or RS232 serial link. The bit 0 of register 321 allows to configure this choice :
• Bit 0 = 0 (default): RS485
• Bit 0 = 1: RS232
On the other hand, a 3-way switch present on the electronic board allows the configuration of the end-of-line resistor and the RS485 bus
polarization:
• Switch 1 = ON (RS-485 bus end-of-line resistor)
• Switches 2 and 3 = ON (RS-485 bus polarization)
The default switch configuration is all channels ON.
Important: in case of RS232 configuration, the 3 channels of the switch must be set to OFF.

4.5. 2-wire RS485 example of wiring

Associated configuration:
• Register 321 : bit 0 = 0 (RS485)
• Switch :
• Int 1 = ON (RS-485 bus end-of-line resistor)
• Int 2 and 3 = ON
+EXTERNAL SUPPLY
- EXTERNAL SUPPLY
(RS-485 bus polarization)
Cable with 7-wire
MODBUS SLAVE
RS-485 2 wires
C (GND)
A
B
V+
GND
CTS (not managed)
+ SLAVE POWER SUPPLY
TX (B)
- SLAVE POWER SUPPLY
RTS (not managed)
RX (A)
GND
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