SD1 Series Inverters Communication Protocol
-117-
Twisted pairs with shied screen
Earth
Earth
Computer
RS485 Rout
Convert from
RS232 to RS485
485-
485+
VFD
Figure 7-1 RS485 wiring diagram for the network with one inverter
7.2.1.2 When multiple inverters are used
In real multi-applications, 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 7-2.
VFD VFD VFD
Address 1
Address n
Earth
485 +
485 -
Earth
485 +
485 -
Earth
485 +
485 -
120 Ohm
Terminal resistor
Computer
Conv
ertor
GND
RS232-485
Max length of
RS: 15m
.
Twisted pair cables with shield screen
Address 2
Figure 7-2 Practical application diagram of chrysanthemum
Figure 7-3 is the star connection. Terminal resistor should be connected to the two devices
which have the longest distance. (1# and 15#device)
1 #
15#
32 #
6
#
Main control
devices
Figure 7-3 Star connection
It is recommended to use shielded cables in multiple connection. The basic parameter of the
devices, such as baud rate and digital check bit in RS485 should be the same and there
should be no repeated address.
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