Parameter download or upload is inactive during the inverter running process. a)
The inverter running is disabled during the process of parameter download or upload. b)
Only the inverter with minimum software version 1.61 of MD320 control board can use the c)
parameter copy keyboard.
During the parameter download or upload process, if the connecting cable of the keyboard d)
is unplugged or loosen, the inverter will report ERR21 protection.
If operation is not completed normally during the parameter download or upload, please check
if the inverter software version is over 1.61 or if the connecting cable is loosen, and repeat the
parameter download or upload.
MD320 series of inverter provides RS232/RS485 communication interface, and adopts
MODBUS communication protocol.User can carry out centralized monitoring through PC/PLC
to get operating requirements.
F.1 About Protocol
This serial communication protocol denes 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 conrmation, returning the
data and error checking etc. If slave takes place the error while it is receiving the information
or cannot nish the action demanded by master, it will send one fault signal to master as a
response.
F.2 Application Methods
The inverter will be connected into a “Single-master Multi-slave” PC/PLC control net with
RS232/RS485 bus.
F.3 Bus structure
(1) Interface mode
RS232/RS485 Hardware interface
(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.
Appendix F MD320 serial communication protocol
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