Salicru CV10-002-S2 User Manual page 75

It is recommended to use shielded cables and make the shield layer as the grounding wires during RS485 remote communication.
In the cases with less devices and shorter distance, it is recommended to use 120Ω terminal resistor as the performance will
be weakened if the distance increase even though the network can perform well without load resistor.
7.2.1.1 Single application
Figure 1 is the site Modbus connection figure of single inverter and PC. Generally, the computer does not have RS485 interface, the
RS232 or USB interface of the computer should be converted into RS485 by converter. Connect the A terminal of RS485 to the
485+ terminal of the inverter and B to the 485- terminal. It is recommended to use the shielded twisted pairs. When applying
RS232-RS485 converter, if the RS232 interface of the computer is connected to the RS232 interface of the converter, the wire
length should be as short as possible within the length of 15m. It is recommended to connect the RS232-RS485 converter to the
computer directly. If using USB-RS485 converter, the wire should be as short as possible, too.
Select a right interface to the upper monitor of the computer (select the interface of RS232-RS485 converter,
such as COM1) after the wiring and set the basic parameters such as communication baud rate and digital
check bit to the same as the inverter.
Figure 1 RS485 physical connection in single application
7.2.1.2 Multi-application
In the real multi-application, the chrysanthemum connection and star connection are commonly used.
Chrysanthemum chain connection is required in the RS485 industrial fieldbus standards. The two ends are
connected to terminal resistors of 120Ω which is shown as figure 2.
Figure 2 Chrysanthemum connection applications
Communication protocol 75 - 104