8000m Series
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Chapter 8 Communication Protocol
8.1 Communication Interface
RS485: asynchronous, half-duplex.
Default: 8-N-1, 9600bps. See FC Group: RS485 Communication Parameters.
8.2 Communication Modes
The protocol is modbus protocol. Besides the common register Read/Write
operation, it is supplemented with commands of parameters management.
The VFD(AC drive) is a slave in the network. It communicates in point to point
master-slave mode. It will not respond to the command sent by the master via
broadcast address.
In the case of multi-drive communication or long-distance transmission,
connecting a 100~120
Ω
resistor in parallel with the master signal line will help to
enhance the immunity to interference.
8.3 Frame Format
8000m series modbus protocol supports only RTU mode. The frame format is
illustrated as follows:
Modbus adopts
“
Big Endian
”
representation for data frame. This means that
when a numerical quantity larger than a byte is transmitted, the most significant
byte is sent first.
