INVT Goodrive350-19 Series Operation Manual page 393

Goodrive350-19 Series VFD for Crane
Baud rate
2400bps
4800bps
In long-distance RS485 communication, it is recommended that you use shielded cables, and use the
shielding layer as the ground wire.
When there are fewer devices and the transmission distance is short, the whole network works well
without terminal load resistors. The performance, however, degrades as the distance increases.
Therefore, it is recommended that you use a 120Ω terminal resistor when the transmission distance is
long.
10.3.1.1 Application to one VFD
Figure 10-1 is the Modbus wiring diagram of one VFD and a PC. Generally, PCs do not provide
RS485 interfaces, and therefore you need to convert an RS232 interface or USB port of a PC to an
RS485 interface. Connect end A of the RS485 communication cable to the 485+ port on the terminal
block of the VFD, and connect end B to the 485- port. It is recommended that you use shielded
twisted pairs. When an RS232-RS485 converter is used, the cable used to connect the RS232
interface of the PC and the converter cannot be longer than 15 m. Use a short cable when possible. It
is recommended that you insert the converter directly into the PC. Similarly, when a USB-RS485
converter is used, use a short cable when possible.
After wiring, select the correct port (such as COM1 to connect the RS232-RS485 converter) on the
upper computer, and set the basic parameters such as baud rate and data bit check consistent with
those of the VFD.
10.3.1.2 Application to multiple VFDs
In practical application to multiple VFDs, chrysanthemum connection and star connection are
commonly used.
Max. transmission
distance
1800m
1200m
Shielded twisted pair
A
B
Ground
RS232-RS485 converter
PC
Figure 10-1 RS485 wiring of one VFD
-381-
Baud rate
9600bps
19200bps
B
RS485 line
Ground
VFD
Communication protocol
Max. transmission
distance
800m
600m
A
485- 485+