MD280/MD280N User Manual Appendix
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Appendix Communication Protocol
MD280 series of inverter provides RS485 communication interface, User
can carry out centralized monitoring through PC/PLC to get operating
requirements. ˄ Set the inverter running command, function code
parameters and read the work status and fault information,etc˅ The
RS232/RS485 conversion device is required if the interface of the external
device is RS232.
1
About Protocol
This serial communication protocol defines the transmission information
and use format in the series communication and it includes master-polling
(or broadcasting) format, master coding method and the content includes
function code of action, transferring data and error checking. The response
of slave is the same structure, and it includes action confirmation, returning
the data and error checking etc. If slave takes place the error while it is
receiving the information or cannot finish the action demanded by master, it
will send one fault signal to master as a response.
2
Application Method
The inverter will be connected into a “Single-master Multi-slave” PC/PLC
control net with RS232/RS485 bus.
3
Bus structure
1˅Interface mode
RS485 Hardware interface. The RS232/RS485 conversion device is
required when the interface of the external device is RS232.
2˅Transmission mode
There provide asynchronous series and half-duplex transmission mode. At
the same time, just one can send the data and the other only receives the
data between master and slave. In the series asynchronous
communication, the data is sent out frame by frame in the form of
message.
3˅Topological mode
In Single-master system, the setup range of slave address is 0 to 247. Zero
refers to broadcast communication address. The address of slave must is
exclusive in the network. That is one condition of one slave machine.
4
Protocol Description
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