PM2.5传感器Modbusrtu通讯协议.doc

PM2. 5传感器Modbus rtu通讯协议-、标准modbus协议说明1、串口设置波特率9600,无校验，数据位8,停止位1力能通讯命令16进制：00 03 00 00 00 01 85 DB （不清楚设备地址可用此找冋） 2、接口说明请接入GND （地\电源负极）,TX （模组串口发对应串口线收），RX （模组串口收对应串 口线发）对应接口调试不通请交换串口线再试4、CRC16校验计算函数（请确认单片机人端编程还是小端）返回 short int参数data【】数组、Ion数组长度例子：datax [8] ={01, 03, 00, 00, 00, 01, 00, 00} 16 进制 unsigned short int x=CRC_16(datax, 6);得到 x=0x840a;six xlx /吓、XT% ZJX Iunsigned short int CRC_16(unsigned char *data, int len)unsigned char *buf;unsigned short int * CRC;unsigned short int crch,crcl; short int i;short int j;char err;buf= & data[len];CRC=(unsigned short int *)buf;buf[0]=0xff;buf[l]=0xff;for (i=0;i>8;crcl=*CRC«8;*CRC=crch+crcl;return(*CRC);/******************函数 CRC_16 () *********小端返回 short int参数data【】数组、len数组长度例子：datax [8] ={01, 03, 00, 00, 00, 01, 00, 00} 16 进制 unsigned short int x=CRC_16(datax,6);得到 X二0x840a;unsigned short int CRC_16(unsigned char *data, int len) { unsigned char *buf;unsigned short int * CRC;unsigned short int crch,crcl;uchar p;uchar j;char err;buf= & data[len];CRC= (unsigned short int *)buf; buf[0]=0xff;//lsbbuf[l]=0xff;//msbfor (p=0;p