A-TS
121
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11. Communication Protocal
11.1 Communication Mode
1
．
Inverter communication protocol is Modbus protocol, and supports the
common register read and write.
2
．
Drive as a slave, master-slave point to point communication. A Master
drive uses broadcast address to send a command, the slave does not
answer.
3
．
In the case of long distance or multi-machine communication, we
recommend to connect the the master station signal GND with the drive
signal "GND", in order to improve the communication of immunity.
11.2 Protocol Format
Modbus protocol supports RTU mode, the corresponding frame format is
as follows:
Srart,at least3.5
bytes idle time
Slave(drive
)address
Function
code
Data
cheksum
Modbus Data frame
RTU mode
End,at least3.5
bytes idle time
Modbus adopts "Big Endian" encoding,firstly transmitting high byte, then
low byte.
RTU Mode: In RTU mode, idle time between frames will take the higher
one among Modbus internal conventional values and function code
setting values. The conventional Min idle frames inside Modbus is as
follows: The idle time passed the bus by the header and trailer is not less
than 3.5 byte time.
Data verification uses CRC-16. The entire information participates in
verification, High&low bytes of checksum can be sent after exchanging.
Specific CRC verification can refer to the example associated with the
protocol. It is worth noting, the idle among frames should keep at least
3.5 bytes at the bus. The start and end idle among frames at the bus
need not to be accumulated.
