modbus_master.c

一个modbus 的主机源代码

tmp[1]=READ_HLD_REG;
tmp[2]= start_address/256;
tmp[3]=start_address & 0xff;
tmp[4]= lenth/256;
tmp[5]= lenth &0xff;
tmp_lenth=6;
construct_rtu_frm ( com_buf,tmp,tmp_lenth);
return 8;
}
/*
4 读取模拟量输入
发送：
*/
int ascii_read_anloginput( unsigned char board_adr,unsigned char *com_buf,int start_address,int lenth) 
{
unsigned char tmp[256],tmp_lenth;
tmp[0]=board_adr;
tmp[1]=READ_AI;
tmp[2]= start_address/256;
tmp[3]=start_address & 0xff;
tmp[4]= lenth/256;
tmp[5]= lenth &0xff;
tmp_lenth=6;
construct_ascii_frm ( com_buf,tmp,tmp_lenth);
return 17;
}
int rtu_read_anloginput( unsigned char board_adr,unsigned char *com_buf,int start_address,int lenth) 

{
unsigned char tmp[256],tmp_lenth;
tmp[0]=board_adr;
tmp[1]=READ_AI;
tmp[2]= start_address/256;
tmp[3]=start_address & 0xff;
tmp[4]= lenth/256;
tmp[5]= lenth &0xff;
tmp_lenth=6;
construct_rtu_frm ( com_buf,tmp,tmp_lenth);
return 8;
}
/*
5 设置继电器
发送：status =0 继电器释放 否则继电器吸合,address 为吸合的继电器编号，0为第一个继电器，依次类推
*/
int ascii_set_coil ( unsigned char board_adr,unsigned char *com_buf,int start_address,int status )
{
unsigned char tmp[256],tmp_lenth;
tmp[0]=board_adr;
tmp[1]=SET_COIL ;
tmp[2]= start_address/256;
tmp[3]=start_address & 0xff;
if ( status )
   {
    tmp[4]= 0xff;
    tmp[5]= 0;
    }
else
    {
    tmp[4]= 0;
    tmp[5]= 0;
        } 

tmp_lenth=6;
construct_ascii_frm ( com_buf,tmp,tmp_lenth);
return 17;
}


int  rtu_set_coil ( unsigned char board_adr,unsigned char *com_buf,int start_address,int status )
{
unsigned char tmp[256],tmp_lenth;
tmp[0]=board_adr;
tmp[1]=SET_COIL ;
tmp[2]= start_address/256;
tmp[3]=start_address & 0xff;
if ( status )
   {
    tmp[4]= 0xff;
    tmp[5]= 0;
    }
else
    {
    tmp[4]= 0;
    tmp[5]= 0;
        } 

tmp_lenth=6;
construct_rtu_frm ( com_buf,tmp,tmp_lenth);
return 8 ;
}
/*
6 设置保持寄存器
*/
int ascii_set_hldreg( unsigned char board_adr,unsigned char *com_buf,int start_address,int value )
{
unsigned char tmp[256],tmp_lenth;
tmp[0]=board_adr;
tmp[1]=SET_HLD_REG;
tmp[2]= start_address/256;
tmp[3]=start_address & 0xff;
tmp[4]= value/256;
tmp[5]= value &0xff;    
tmp_lenth=6;
construct_ascii_frm ( com_buf,tmp,tmp_lenth);
return 17;
}
int rtu_set_hldreg( unsigned char board_adr,unsigned char *com_buf,int start_address,int value )
{
unsigned char tmp[256],tmp_lenth;
tmp[0]=board_adr;
tmp[1]=SET_HLD_REG;
tmp[2]= start_address/256;
tmp[3]=start_address & 0xff;
tmp[4]= value/256;
tmp[5]= value &0xff;    
tmp_lenth=6;
construct_rtu_frm ( com_buf,tmp,tmp_lenth);
return 8 ;
}
/*
7
接收分析：
dest_p 接收到数据指针
sourc_p 串口接收缓冲区指针
data_start_address 开始地址
*/

/* RTU  接收分析 */
int rtu_data_anlys( int   *dest_p,unsigned char *source_p,int data_start_address,int fr_lenth)
{
   unsigned short crc_result,crc_tmp;
   unsigned char tmp1,tmp2,shift;
   
   crc_tmp=*( source_p+fr_lenth-2);
   crc_tmp=crc_tmp * 256 + *( source_p+fr_lenth-1);
   crc_result = crc( source_p,fr_lenth-2);
 
   
   if ( crc_tmp !=crc_result ) 
    {
     hld_reg[0x31]++;
     return -1;
    }
   switch ( *(source_p+1) )
    {
    case READ_COIL:                   /*读取继电器状态 */
    for ( tmp1=0;tmp1<*( source_p+2) ;tmp1++)
    {
     shift=1;
     for ( tmp2=0;tmp2<8;tmp2 ++)
     { 
      *(dest_p+data_start_address+tmp1*8+tmp2)= shift & *( source_p+3);
      *( source_p+3)>>=1;
 

     }
    }
    break;

    case READ_DI: /*读取开关量输入*/
     for ( tmp1=0;tmp1<*( source_p+2);tmp1++)
    {
     shift=1;
     for ( tmp2=0;tmp2<8;tmp2 ++)
     { *(dest_p+data_start_address+tmp1*8+tmp2)= shift & *( source_p+3);
     *( source_p+3)>>=1;
 
     
     }
    }
    break;

    case READ_HLD_REG:  /*读取保持寄存器*/
     for ( tmp1=0;tmp1<*( source_p+2);tmp1+=2)
     {
       *(dest_p + data_start_address+ tmp1/2)= *( source_p+tmp1+3)*256 +  *( source_p+tmp1+4) ;
 
       
     }
    break ;

    case 4:      /*读取模拟量输入*/
    for ( tmp1=0;tmp1<*( source_p+2);tmp1+=2)
     {
      *(dest_p + data_start_address+ tmp1/2)= *( source_p+tmp1+3)*256 +  *( source_p+tmp1+4) ;
 
      
     }
    break;

    case PROTOCOL_EXCEPTION:
    return -1*PROTOCOL_ERR;   
    break;

    default:
    return -1*PROTOCOL_ERR;
    break;
   }


  return 0;
   
	
}
	
	
int  ascii_data_anlys( int   *dest_p,char *source_p,int data_start_address)
{
   unsigned char tmp[256];
   int lenth;
   int tmp1,tmp2;
   char shift;

   lenth= asctortu(tmp,source_p);
   if ( lenth==0) return -1* FRM_ERR;
   switch ( tmp[1] )
   {
    case READ_COIL:                   /*读取继电器状态 */
    for ( tmp1=0;tmp1<tmp[2];tmp1++)
    {
     shift=1;
     for ( tmp2=0;tmp2<8;tmp2 ++)
     { *(dest_p+data_start_address+tmp1*8+tmp2)= shift & tmp [tmp1+3];
 
     tmp [tmp1+3]>>=1;
     }
    }
    break;

    case READ_DI: /*读取开关量输入*/
     for ( tmp1=0;tmp1<tmp[2];tmp1++)
    {
     shift=1;
     for ( tmp2=0;tmp2<8;tmp2 ++)
     { *(dest_p+data_start_address+tmp1*8+tmp2)= shift & tmp [tmp1+3];
     tmp [tmp1+3]>>=1;     
     }
    }
    break;

    case READ_HLD_REG:  /*读取保持寄存器*/
     for ( tmp1=0;tmp1<tmp[2];tmp1+=2)
     {
       *(dest_p + data_start_address+ tmp1/2)= tmp[tmp1+3]*256 +  tmp[tmp1+4] ;
       
     }
    break ;

    case 4:      /*读取模拟量输入*/
    for ( tmp1=0;tmp1<tmp[2];tmp1+=2)
     {
       *(dest_p+data_start_address+ tmp1/2)= tmp[tmp1+3]*256 +  tmp[tmp1+4] ;
      
     }
    break;

    case PROTOCOL_EXCEPTION:
    return -1*PROTOCOL_ERR;   
    break;

    default:
    break;
   }


  return 0;

}

/*
主程序按照一定的顺序调用 1～6子程序，然后把生成的缓存内容写入串口。
接收到数据送给7的子程序分析即可。
ASCII 方式下，用0X0D,0X0A作为帧结束判断的依据
RTU方式下，以两个字节间的时间间隔大于3.5倍的一个字符周期为帧结束判断依据
READ() WRITE()是两个假想存在的函数 
*/

/*void main ( void)
{
ascii_read_coil_status ( 1,tx_buf,0,8); 	
write (com1,tx_buf );
read  (com1,rx_buf);
ascii_data_anlys( coil,rx_buf,0);

ascii_read_input_status ( 1,tx_buf,0,8); 	
write ( com1,tx_buf );
read  (com1, rx_buf);
ascii_data_anlys( di,rx_buf,0);	

ascii_read_hldreg ( 1,tx_buf,0,8); 	
write ( com1,tx_buf );
read  (com1, rx_buf);
ascii_data_anlys( hld_reg,rx_buf,0);

ascii_read_anloginput( 1,tx_buf,0,8); 	
write ( com1,tx_buf );
read  (com1, rx_buf);
ascii_data_anlys( ai,rx_buf,0);

ascii_set_coil (1,tx_buf,0,1); //第一个继电器吸合/
write ( com1,tx_buf );
read  (com1, rx_buf);
ascii_data_anlys( di,rx_buf,0);	

ascii_set_coil (1,tx_buf,0,0); //第一个继电器释放/
write ( com1,tx_buf );
read  (com1, rx_buf);
ascii_data_anlys( di,rx_buf,0);	
	
}*/