RS485通信程序。Modbus协议 ASCII模式

使用ASCII模式，消息包括了一基于LRC方法的错误检测域。

LRC域检测了消息域中除开始的冒号及结束的回车换行号外的内容。

LRC域是一个包含一个8位二进制值的字节。

LRC值由传输设备来计算并放到消息帧中，接收设备在接收消息的过程中计算LRC，

并将它和接收到消息中LRC域中的值比较，如果两值不等，说明有错误。

LRC方法是将消息中的8Bit的字节连续累加，丢弃了进位。-RS485 communication program. Modbus protocol ASCII mode

Using ASCII mode, the message includes an error detection method based LRC domain.

LRC field testing in addition to the beginning of the message field colon and end carriage return line numbers outside content.

LRC field is a binary value that contains an 8-bit byte.

LRC value calculated by the transmission device and into the message frame, the receiving device receiving the message in the process of calculation LRC,

Receives the message and place it in the LRC field value, and if the two values ​ ​ are unequal, there is an error.

LRC is the message of the continuous accumulation of bytes 8Bit, discarding the carry bit.