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3 INSTALLATION OF THE EQUIPMENT IN NETWORK
For the connection of the frequency inverter CFW320 using the RS485 interface, the following points must be
observed:
3.1 COMMUNICATION RATE
The RS485 interfaces of the CFW320 frequency inverter can communicate using the rates defined on the
on page
10.
All network equipment must be programmed to use the same communication baud rate.
3.2 ADDRESS IN THE MODBUS RTU NETWORK
Each Modbus RTU network device must have an address, and may range from 1 to 247. This address must be
unique for each equipment.
3.3 TERMINATION RESISTOR
The use of termination resistors at the ends of the bus is essential to avoid line reflection, which can impair the
signal and cause communication errors. Termination resistors of 120 Ω | 0.25 W must be connected between the
signals +B and -A at the ends of the main bus.
It worth to mention that, in order to allow the disconnection of the element from the network without damaging the
bus, it is interesting to put active terminations, which are elements that only play the role of the termination. Thus,
any equipment in the network can be disconnected from the bus without damaging the termination.
3.4 CABLES
Recommended characteristics of the cable used in the installation:
It is recommended the use of a shielded cable with a twisted pair for the signals +B and -A, 24 AWG minimum.
It is also recommended that the cable has one more wire for the interconnection of the 0V reference signal.
Maximum length for connection between devices: 1000 m.
To perform the installation, it is recommended the use of shielded cables specific for use in industrial environment.
3.5 CONNECTION IN THE NETWORK
In order to interconnect the several network nodes, it is recommended to connect the equipment directly to the
main line without using derivations. During the cable installation the passage near to power cables must be avoided,
because, due to electromagnetic interference, this makes the occurrence of transmission errors possible.
INSTALLATION OF THE EQUIPMENT IN NETWORK
Table 3.1: Supported baud rates
Baud Rate
9600 bit/s
19200 bit/s
38400 bit/s
57600 bit/s
76800 bit/s
Table 3.1
CFW320 | 10
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