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modbus rtu 如何读保持寄存器

linjj6566    2012-02-28    RTU    浏览 411 次

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wowhyfwow 发布日期:2012-02-29
/******************头文件定义******************/
#include
#include
#include
#include
#include
#include
#include
#include
#define max_buffer_size 100 /*定义缓冲区Z大宽度*/
/*******************************************/
int fd; /*定义设备文件描述符*/
int flag_close;

static unsigned char table_crc_hi[] = {
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
};
static unsigned char table_crc_lo[] = {
0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06,
0x07, 0xC7, 0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD,
0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09,
0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A,
0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC, 0x14, 0xD4,
0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,
0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3,
0xF2, 0x32, 0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4,
0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A,
0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29,
0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF, 0x2D, 0xED,
0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,
0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60,
0x61, 0xA1, 0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67,
0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F,
0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68,
0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA, 0xBE, 0x7E,
0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,
0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71,
0x70, 0xB0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92,
0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C,
0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x, 0x9A, 0x9B, 0x5B,
0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4B, 0x8B,
0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,
0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42,
0x43, 0x83, 0x41, 0x81, 0x80, 0x40
};
int open_serial(int k)
{
if(k==0) /*串口选择*/
{
fd = open("/dev/ttyS0",O_RDWR|O_NOCTTY); /*读写方式打开串口*/
perror("open /dev/ttyS0");
}
else
{
fd = open("/dev/ttyS1",O_RDWR|O_NOCTTY);
perror("open /dev/ttyS1");
}
if(fd == -1) /*打开失败*/
return -1;
else
return 0;
}
static unsigned short int crc(unsigned char *buffer, unsigned short int buffer_length)//计算CRC校验码
{
unsigned char crc_hi = 0xFF; /* high CRC byte initialized */
unsigned char crc_lo = 0xFF; /* low CRC byte initialized */
unsigned int i; /* will index into CRC lookup */

/* pass through message buffer */
while (buffer_length--) {
i = crc_hi ^ *buffer++; /* calculate the CRC */
crc_hi = crc_lo ^ table_crc_hi[i];
crc_lo = table_crc_lo[i];
}

return (crc_hi << 8 | crc_lo);
}
int main(int argc, char *argv[ ] )
{
unsigned char sbuf[20];/*待发送的内容,以\n 为结束标志*/
sbuf[0] = 0x01; //Device id
sbuf[1] = 0x06; //功能码 读保持寄存器是06(多个)
sbuf[2] = 0x00;
sbuf[3] = 0x6B; //start address(2 bytes)
sbuf[4] = 0x00;
sbuf[5] = 0x03; //the number of registers(2 bytes)

unsigned short int temp; //calculate the CRC
unsigned char crc_hi;

unsigned char crc_lo;
temp = crc(sbuf,6);

crc_hi = temp >> 8;

crc_lo = temp & 0x00FF;
sbuf[6] = crc_hi;
sbuf[7] = crc_lo;
int sfd,retv,i;
struct termios option;
int length=8;/*发送缓冲区数据宽度*/

open_serial(0); /*打开串口1*/

printf("ready for sending data...\n"); /*准备开始发送数据*/
tcgetattr(fd,&option);
cfmakeraw(&option);

cfsetispeed(&option,B9600); /*波特率设置为9600bps*/
cfsetospeed(&option,B9600);

tcsetattr(fd,TCSANOW,&option);
for(i=0;i {
printf("[%0x]",sbuf[i]);
}
printf("\n");
retv=write(fd,sbuf,length); /*send数据*/
if(retv==-1)
{
perror("write");
}
printf("the number of char sent is %d\n",retv);
ioctl(fd,TCFLSH,0);

unsigned char rbuf[max_buffer_size]; /*定义接收缓冲区*/
int flag_close, retv1,j,ncount=0;

printf("ready for receiving data...\n");
retv1=read(fd,rbuf,20); /*接收数据*/
if(retv1==-1)
{
perror("read"); /*读状态标志判断*/
}

printf("The data received is:\n"); /*输出接收到的数据*/
for(j=0;j {
printf("[%0x]",rbuf[j]);
}
printf("\n");

flag_close =close(fd);
if(flag_close ==-1) /*判断是否成功关闭文件*/
printf("Close the Device failur!\n");
return 0;
}
你自己看着改吧,我也刚学。
全部评论
heshaxiang 发布日期:2012-03-10
如果有串口软件,用03码读取内部寄存器就可以了。
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