Modbus TCP 读写COIL(BOOL),Register(int/float)的c++代码

这几天做Modbus的PLC控制，实现代码：

BOOL读取

#define SIGN_ID (1)

int readBool( unsigned short nAddr )
{
//读取COIL(BOOL)数据
	//nAddr = 1;
	unsigned char buf[12];
	unsigned char chHByte = HIBYTE(nAddr);
	unsigned char chLByte = LOBYTE(nAddr);
	buf[0] = chHByte;  
	buf[1] = chLByte;  //为此次通信事务处理标识符   2Bit 

	buf[2] = 0x00;
	buf[3] = 0x00;  //表示该条指令遵循ModbusTCP协议

	buf[4] = 0x00;
	buf[5] = 0x06;  //表示后面数据的长度，可以自己数一下是否是6个Bit

	buf[6] = SIGN_ID;  //设备地址

	buf[7] = CODE_BOOL_READ;  //读写的功能码

	buf[8] = chHByte;
	buf[9] = chLByte;  //线圈的地址

	//读取此地址开始的1个coil值
	buf[10] = 0x00; 
	buf[11] = 0x01; //寄存器的长度

	return ( sizeof(buf) == SendData( buf, sizeof(buf) )?1:0);
}

int writeBool( unsigned short nAddr, bool bValue )
{
//写入COIL(BOOL)数据

	unsigned char buf[14];
	unsigned char chHByte = HIBYTE(nAddr);
	unsigned char chLByte = LOBYTE(nAddr);
	buf[0] = chHByte;  
	buf[1] = chLByte;  //为此次通信事务处理标识符   2Bit 

	buf[2] = 0x00;
	buf[3] = 0x00;  //表示该条指令遵循ModbusTCP协议

	buf[4] = 0x00;
	buf[5] = 0x08;  //表示后面数据的长度，可以自己数一下是否是6个Bit

	buf[6] = SIGN_ID;  //设备地址

	buf[7] = CODE_BOOL_WRITE;  //读写的功能码

	buf[8] = chHByte;
	buf[9] = chLByte;  //寄存器的地址
	
	//buf[10] = 0x00;
	//buf[11] = 0x01;  //寄存器的地址
	//写入1个coil值
	if( bValue )
	{
		buf[10] = 0xFF; 
		buf[11] = 0x00; //数值
	}
	else
	{
		buf[10] = 0x00; 
		buf[11] = 0x00; //数值
	}

	return ( sizeof(buf) == SendData( buf, sizeof(buf) )?1:0);

}

int readInt( unsigned short nAddr )
{
//读取int数据

	unsigned char buf[12];
	unsigned char chHByte = HIBYTE(nAddr);
	unsigned char chLByte = LOBYTE(nAddr);
	buf[0] = chHByte;  
	buf[1] = chLByte;  //为此次通信事务处理标识符   2Bit 

	buf[2] = 0x00;
	buf[3] = 0x00;  //表示该条指令遵循ModbusTCP协议

	buf[4] = 0x00;
	buf[5] = 0x06;  //表示后面数据的长度，可以自己数一下是否是6个Bit

	buf[6] = SIGN_ID;  //设备地址

	buf[7] = CODE_INT_READ;  //读写的功能码

	buf[8] = chHByte;
	buf[9] = chLByte;  //寄存器的地址

	//hold register的长度是16bit即2字节
	buf[10] = 0x00; 
	buf[11] = 0x01; //寄存器的长度

	return ( sizeof(buf) == SendData( buf, sizeof(buf) )?1:0);

}

int writeIntMessage( unsigned short nAddr, int nValue )
{
//写入int数据
	unsigned char buf[17];
	unsigned char chHByte = HIBYTE(nAddr);
	unsigned char chLByte = LOBYTE(nAddr);
	buf[0] = chHByte;  
	buf[1] = chLByte;  //为此次通信事务处理标识符   2Bit 

	buf[2] = 0x00;
	buf[3] = 0x00;  //表示该条指令遵循ModbusTCP协议

	buf[4] = 0x00;
	buf[5] = 0x09;  //表示后面数据的长度

	buf[6] = SIGN_ID;  //设备地址

	buf[7] = CODE_INT_WRITE;  //读写的功能码

	buf[8] = chHByte;
	buf[9] = chLByte;  //寄存器的地址

	/* 寄存器数目 */
	buf[10] = 0x00;
	buf[11] = 0x01;

	/*接下来的字节数目*/
	buf[12] = 0x02;

	//hold register的长度是16bit即2字节
	unsigned char* pBuffer = (unsigned char*)&nValue;
	buf[13] = pBuffer[1]; 
	buf[14] = pBuffer[0]; //数据

	return ( sizeof(buf) == SendData( buf, sizeof(buf) )?1:0);

}

int readFloat( unsigned short nAddr )
{
//读取float数据

	unsigned char buf[12];
	unsigned char chHByte = HIBYTE(nAddr);
	unsigned char chLByte = LOBYTE(nAddr);
	buf[0] = chHByte;  
	buf[1] = chLByte;  //为此次通信事务处理标识符   2Bit 

	buf[2] = 0x00;
	buf[3] = 0x00;  //表示该条指令遵循ModbusTCP协议

	buf[4] = 0x00;
	buf[5] = 0x06;  //表示后面数据的长度，可以自己数一下是否是6个Bit

	buf[6] = SIGN_ID;  //设备地址

	buf[7] = CODE_REAL_READ;  //读写的功能码

	buf[8] = chHByte;
	buf[9] = chLByte;  //寄存器的地址

	//hold register的长度是16bit即2字节
	buf[10] = 0x00; 
	buf[11] = 0x02; //寄存器的长度

	return ( sizeof(buf) == SendData( buf, sizeof(buf) )?1:0);
}

int writeFloat( unsigned short nAddr, float fValue )
{
	//写入float数据

	unsigned char buf[17];
	unsigned char chHByte = HIBYTE(nAddr);
	unsigned char chLByte = LOBYTE(nAddr);
	buf[0] = chHByte;  
	buf[1] = chLByte;  //为此次通信事务处理标识符   2Bit 

	buf[2] = 0x00;
	buf[3] = 0x00;  //表示该条指令遵循ModbusTCP协议

	buf[4] = 0x00;
	buf[5] = 0x0B;  //表示后面数据的长度

	buf[6] = SIGN_ID;  //设备地址

	buf[7] = CODE_REAL_WRITE;  //读写的功能码

	buf[8] = chHByte;
	buf[9] = chLByte;  //寄存器的地址

	/* 寄存器数目 */
	buf[10] = 0x00;
	buf[11] = 0x01;

	/*接下来的字节数目*/
	buf[12] = 0x04;
	
	//hold register的长度是16bit即2字节
	unsigned char* pBuffer = (unsigned char*)&fValue;
	buf[13] = pBuffer[1]; 
	buf[14] = pBuffer[0]; //数据

	buf[15] = pBuffer[3]; 
	buf[16] = pBuffer[2]; //数据

	return ( sizeof(buf) == SendData( buf, sizeof(buf) )?1:0);
}

modbus server反馈

#if !defined(MAKEWORD)
#define MAKEWORD(low,high) \
        ((WORD)(((BYTE)(low)) | ((WORD)((BYTE)(high))) << 8))
#endif

void handleBoolMsg( unsigned short nAddr, bool bValue)
{
	printf("读取0x%04X的BOOL值为:%s", nAddr, bValue?"true":"false");
}

void handleIntMsg( unsigned short nAddr, bool bValue)
{
	printf("读取0x%04X的int值为:%d", nAddr, nValue);
}


void handleFloatMsg( unsigned short nAddr, float fValue)
{
	printf("读取0x%04X的float值为:%f", nAddr, fValue );
}

void onReceived( const char* pData, unsigned long lLen )
{
	if( lLen > 8 )
	{
		unsigned short nType = MAKEWORD(pData[1], pData[0] );
		/* 读取反馈 */
		if( 0 == pData[2] && 0 == pData[3] &&
			pThis ->m_cID == pData[6] )
		{
			unsigned char chFunctionCode = pData[7];

			/* 数据的长度 */
			unsigned char nDataLen = pData[8];
			if( 1 == nDataLen )
			{

				if( CODE_BOOL_READ == chFunctionCode )
				{ /* 读取BOOL */
					handleBoolMsg( nType, 0x00 != (pData[9]&0x01) );
				}
			}
			else if( 2 == nDataLen )
			{
				if( CODE_INT_READ == chFunctionCode )
				{
					int nValue = (0X0000FFFF&MAKEWORD( pData[10],pData[9] ) );
					handleIntMsg( nType, nValue );
				}
			}
			else if( 4 == nDataLen )
			{
				if( CODE_REAL_READ == chFunctionCode )
				{
					int nValue = (0X0000FFFF&MAKEWORD( pData[10],pData[9] ) ) |
						( ( 0X0000FFFF&MAKEWORD( pData[12],pData[11] ) ) << 16);

					handleFloatMsg( nType, *(float*)&nValue );
				}
			}
		}
	}
	else
	{ /* 读取反馈 */
		//错误解析,暂略
	}
}

用到的地址信息

#define CODE_BOOL_READ		(0x01)			 /*BOOL 读功能码 */
#define CODE_BOOL_WRITE		(0x05)/*(0x0F)*/ /*BOOL 写功能码 */
#define CODE_INT_READ		(0x03)			 /*INT  读功能码 */
#define CODE_INT_WRITE		(0x10)			 /*INT  写功能码 */
#define CODE_REAL_READ		CODE_INT_READ	 /*REAL 读功能码 */
#define CODE_REAL_WRITE		CODE_INT_WRITE   /*REAL 写功能码 */