INVT Goodrive350-19 Series Operation Manual page 417

Goodrive350-19 series VFD for crane
Baud rate (bps)
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 120 Ω terminal resistor when the transmission distance
is long.
10.3.1.1 When one VFD is used
Figure 10-1 is the Modbus wiring diagram for the network with one VFD and PC. Generally, PCs do
not provide RS485 interfaces, and therefore you need to convert an RS232 or USB interface of a PC
to an RS485 interface through a converter. Then, connect end A of the RS485 interface 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.
When the wiring is completed, select the correct port (for example, COM1 to connect to the
RS232-RS485 converter) for the upper computer of the PC, and keep the settings of basic
parameters such as communication baud rate and data check bit consistent with those of the VFD.
Figure 10-1 RS485 wiring diagram for the network with one VFD
10.3.1.2 When multiple VFDs are used
In the network with multiple VFDs, chrysanthemum connection and star connection are commonly
used.
According to the requirements of the RS485 industrial bus standards, all the devices need to be
Max. transmission
distance (meter)
1800m
1200m
Shielded twisted pair
A B
Ground
RS232-RS485 converter
PC
-405-
Baud rate (bps)
9600BPS
19200BPS
B
RS485 line
Ground
VFD
Communication protocol
Max. transmission
distance (meter)
800m
600m
A
485- 485+