CT100 inverter Communication protocol
154
Slave response message
High bit of F00.09 address
00H (Function code group)
Low bit of F00.09 address
Check mode-CRC (Cyclical Redundancy Check) check
The checkout uses RTU frame format. The frame includes the frame error
detection field which is based on the CRC calculation method. The CRC field is
two bytes including 16 figure binary values. It is added into the frame after
calculated by transmitting device. The receiving device recalculates the CRC of
the received frame and compares them with the value in the received CRC field.
If the two CRC values are different, there is an error in the communication.
Using the RTU frame format, the message includes an error detection field
based on the CRC method. The CRC field detects the contents of the entire
message. The CRC field is two bytes and contains a 16-bit binary value. It is
added to the message by the transmission device. 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 are not equal, the
transmission has an error.
During CRC, 0*FFFF will be stored. And then, deal with the continuous 6-above
bytes in the frame and the value in the register. Only the 8Bit data in every
character is effective to CRC, while the start bit, the end and the odd and even
check bit is ineffective.
The calculation of CRC applies the international standard CRC checkout
principles. When you are editing CRC calculation, you can refer to the relative
standard CRC calculation to write the required CRC calculation program.
Here provided a simple function of CRC calculation for the reference
(programmed with C language)
unsigned int crc_cal_value(unsigned char*data_value,unsigned char
data_length)
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