3.5-
character
time
Action：It will return error if no successful.
8.6 Cyclical Redundancy Check
In RTU mode, messages include an error-checking field that is based on a CRC
method. The CRC field checks the contents of the entire message. The CRC field is
two bytes, containing a 16-bit binary value. The CRC value is calculated by the
transmitting device, which appends the CRC to the message. The receiving device
recalculates a CRC during receipt of the message, and compares the calculated value
to the actual value it received in the CRC field. If the two values are not equal, an
error results.
The CRC is started by 0xFFFF.Then a process begins of applying successive
eight-bit bytes of the message to the current contents of the register. Only the eight
bits of data in each character are used for generating the CRC. Start and stop bits,
and the parity bit, do not apply to the CRC.
During generation of the CRC, each eight-bit character is exclusive O Red with
the register contents. Then the result is shifted in the direction of the least significant
bit (LSB), with a zero filled into the most significant bit (MSB) position. The LSB is
extracted and examined. If the LSB was a 1, the register is then exclusive O Red
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