STX            ADDR         FUNC       LEN                                                          DATA                                   LRC                END
启始单元 通讯位置     功能码       资料长度                                                 资料内容:2 个ASCII组合
                                                         设定：   设定：1个word时LEN=3       成N个Byte,最多有50个                                     
                                                           1个  Byte时<1Byte时LEN =2               ASCII 
对01变频器写入30.00Hz（写入CD000）
STX                   ADDR            FUNC              LEN              DATA                    LRC                   END                                                                        

:                        0  1                 0   2                  03                 0  0  0  B  B  B     3  7