Vicruns VD120 Series, Руководство пользователя

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VD120 Series Inverter User Manual Communication Protocol
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When the first field (address information) is received, each network device acknowledges the byte.
With the completion of the last byte transfer, there is a similar 3.5 byte transmission time interval,
used to identify the end of this frame, after which, will start a new frame transmission.
The information of a frame must be transmitted in a continuous data stream. If there is more than 3.5
bytes of interval time before the end of the entire frame transmission, the receiving device will clear
the incomplete information and erroneously assume that the next byte is new similarly, if the interval
between the start of a new frame and the previous frame is less than 3.5 bytes, the receiving device
will consider it to be the continuation of the previous frame. Because of the frame disorder, the final
CRC Check the value is not correct, resulting in communication failure.
The standard structure of RTU frame:
Frame header START T1-T2-T3-T4(3.5 Bits transmission time)
Slave address field ADDR
Communication address: 0~247(decimal)
(0 as broadcast address)
Function field CMD
03H: read slave parameter
06H: write slave parameter
Data field
DATA (N-1)…DATA (0)
2*N Bit data: this part is the main content of
communication, also as the core of data exchange
in communication
CRC CHK low Bit
CRC CHK high Bit
Detect value: CRC verify value (16Bit)
Tail Frame END T1-T2-T3-T4 (3.5 Bits transmission time)
9.6 Command Code and Communication Data Description
9.6.1 Command code: 03H (0000 0011), reads N words. (There are 16characters can be read at
the most.)
For example: the inverter slave address is 01H, memory start address is 1001H (running frequency
address), read 5Bits continuously (running frequency, bus voltage, output voltage, output current,
output power total 5 data of run parameter), the frame of structure as below:
RTU master command message
START T1-T2-T3-T4
ADDR 01H
CMD 03H
Start address high Bit 10H
Start address low Bit 01H
Data Bit high Bit 00H
Data Bit low Bit 05H
CRCCHK low Bit D0H