GE DS200RTBAG3AGC继电器卡
如果从从机发送的功能代码的高阶位为1（即，如果功能代码>127），则从机未按要求执行功能，并发送错误或异常响应。•数据：这将是一个可变的字节数，取决于FUNCTION CODE。这可能是主设备向从设备或从设备向主设备发送的实际值、设置点或地址。有关支持的功能和每个功能所需数据的说明，请参阅第3节。•CRC：这是一个两字节的错误检查代码。错误检查Modbus的RTU版本包括每次传输的2字节CRC-16（16位循环冗余检查）。CRC-16算法本质上将整个数据流（仅数据位；忽略开始、停止和奇偶校验）视为一个连续的二进制数。该数字首先左移16位，然后除以特征多项式（11000000000101B）。16位余数被附加到传输的末尾，先是MSByte。。
If the high order bit of the FUNCTION CODE sent from the slave is a 1 (i.e. if the FUNCTION CODE is > 127) then the slave did not perform the function as requested and is sending an error or exception response. • DATA: This will be a variable number of bytes depending on the FUNCTION CODE. This may be Actual Values, Setpoints, or addresses sent by the master to the slave or by the slave to the master. See section 3 for a description of the supported functions and the data required for each. • CRC: This is a two byte error checking code.Error Checking The RTU version of Modbus includes a 2-byte CRC-16 (16-bit cyclic redundancy check) with every transmission. The CRC-16 algorithm essentially treats the entire data stream (data bits only; start, stop and parity are ignored) as one continuous binary number. This number is first shifted left 16 bits and then divided by a characteristic polynomial (11000000000000101B). The 16-bit remainder is appended to the end of the transmission, MSByte first.
