The parity from the Chinese industrial control network serial data during transmission, due to the error, for example, the transmission character 'e', each of which may be: 0100, 0101 = 45h D0 Due to interference, the position may make the position becomes 1. In this case, we call "error". How do we discover the mistakes in the transmission, called "error". After discovering errors, how to eliminate errors and call "Correction". The simplest error detection method is "parity", that is, in addition to the transmitted characters, then transmits 1 qi / doll bit. You can use a cheap or even check. Odd calibration: All the number of transmitted digits (including the number and check digits of characters), the number of "1" is odd, such as: 1 0110, 0101 0 0110 ,0001 Even quotes: Number of transfer (including In each of the characters, the number of "1" is an even number, such as: 1 0100, 0101 0 0100,0001 Parity can detect partial error in the information transmission process (1 bit error can The detection, 2 and 2 or more error cannot be detected, and it cannot correct. After discovering errors, it can only be reused. However, due to its simple implementation, it is still widely used. Some error-wrong methods have automatic error correction. Such as circular redundant code (CRC) error, etc.
