Vicruns 2S-0.4G-B, User Manual

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Chapter 10 Appendix
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Frame header Slave address
Read trouble
codes 0×83
Error type
CRC check
L...H
Finish
Calculate CRC check
≥ 3 . 5 Character 1 Byte 1 Byte 1 Byte 2 Byte
Slave write response error frame
Frame header Slave address
Write fault code
0×86
Error type
CRC check
L...H
Finish
Calculate CRC check
≥ 3 . 5 Character 1 Byte 1 Byte 1 Byte 2 Byte
Example: read the contents of two consecutive parameters starting from P0-03 of the inverter
whose slave address P8-02 is 01.
The frame sent by the host is shown in the figure:
Frame header
≥ 3.5 Character
Slave address
0×01
Read command
code 0×03
Function code
address 0×F0
0×03
Number of read
function codes
0×00 0×02
CRC check
0×07 0×0B
Finish
The slave reply frame is as shown in the figure:
Frame header
≥ 3.5
Character
Slave address
0×01
Read
command
code 0×03
Data bytes
0×04
P0.03
parameter
value 0×00
0×00
P0.04
parameter
value 0×00
0×00
CRC check
0×FA 0×33
Finish
Note: If the write command is unsuccessful, the failure reason will be returned.
6.Check method (CRC check method)
CRC (Cyclical Redundancy Check) uses the RTU frame format, and the message includes
an error detection field based on the CRC method. The CRC field detects the content of the
entire message. The CRC field is two bytes containing a 16-bit binary value. It is calculated
by the transmitting device and added to the message. The receiving device recalculates the
CRC of the received message and compares it with the value in the received CRC field. If the
two CRC values a
​​ re not equal, it means that there is an error in the transmission.
The CRC is stored in 0xPFPF first, and then a process is called to process the consecutive 8-
bit bytes in the message with the value in the current register. Only the 8Bit data in each cha-
racter is valid for CRC, and the start and stop bits and parity bits are invalid.
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