Alpha 6000S series User Manual page 27

Chapter 2 Installation and Wiring
Upper computer
Pin No.
Signal
Enclosure
Fig. 2-37 Wiring diagram between the upper computer and the inverter interface
When multiple inverters are connected in one RS485 system, the communication suffers more interference,
and a maximum of 31 inverters can be connected through RS485 serial bus. Wiring is very important.
Communication bus must be shielded twisted pair wiring. The following connection method is recommended:
PLC
SG
485+ 485-
Fig. 2-38 Recommended wiring diagrams (inverters and motors are all well grounded) when PLC is in multi
When a PC is used as the host machine, a RS232/RS485 bus adapter should be added between the host machine and
the bus; when a PLC controller is used as the host machine, connect the dotted terminals, namely RS485 terminal of
slave-based machine and RS485 terminal of the host machine.
When multiple 35R5GB and above inverters compose RS485 bus communication, the matched resistance toggle
switch SW6 on the control board of this series of inverters at the farthest ends of the bus should be turned to ON
position, as shown in Fig. 2-39.
Fig. 2-39 Schematic illustration of RS485 matched resistance toggle switch
If using the above wiring still cannot communicate normally, the following measures can be taken:
1) Supply the PLC controller (or the upper machine) separately or isolate its power;
2) When using a RS232/RS485 converter module, separate power supply for the modular converter can be
considered. And modular converter with opto-coupler isolation is recommended to use;
3) Apply a magnetic ring on the communication line, and reduce the carrier frequency of the converter
appropriately if site conditions permit.
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RS232/RS485 converter
Terminal name
Shielded
cable
Terminal name
Negative terminal of
signal
Positive terminal of
signal
Inverter
变频器
485+ 485-
GND
computer communication with inverters
Description of terminal
Positive terminal of 5V
power supply
TXD
RXD
Negative terminal of 5V
power supply
Description of terminal
Inverter
变频器
GND
485+ 485-
Shield line
屏蔽线
Inverter
RS485 communication interface
Terminal name Description of terminal
Negative terminal of
signal
Positive terminal of
signal
Inverter
变频器
GND
485+ 485-