在VC中使用DLL一般都是采用动态声明的方式，函数说明中给出的是Delphi的函数原型，

在VC中声明时只要注意一下类型的对应即可,Delphi中的longint类型对应VC中的int类型

Delphi中的Pchar对应VC中的char* ，下面给出主要函数的声明：

在使用的文件的cpp中声明一个句柄：

HINSTANCE hinstDLL;

用来标识导入的动态链接库。

1)、按下例说明声明相关各个函数：(在cpp文件的头处声明)

typedef int (_stdcall *pOpen)(int nport, int BaudRate, int DataBits, char* Parity, int StopBits, char* User);
typedef int (_stdcall *pClose)(int nport);
typedef int (_stdcall *pSetDelay)(int nport);
typedef int (_stdcall *pComTrue)(int nport);
typedef int (_stdcall *pComWork)(int nport);

typedef int (_stdcall *pMS)(int nport, int node);
typedef int (_stdcall *pSC)(int nport, int node, int State);
typedef int (_stdcall *pMM)(int nport, int node);
typedef int (_stdcall *pTS)(int nport, int node);
typedef int (_stdcall *pReadInt)(int nport, int node, int address, int Count, char* Order, int* RxdBuffer);
typedef int (_stdcall *pReadTc)(int nport, int node, int address, int Count, int* RxdBuffer);
typedef int (_stdcall *pWriteInt)(int nport, int node, int address, int Count, char* Order, int* TxdBuffer);

typedef int (_stdcall *pSetF)(int nport, int node, int address, int Bit, char* Order);
typedef int (_stdcall *pReSetF)(int nport, int node, int address, int Bit, char* Order);
typedef int (_stdcall *pCancelF)(int nport, int node, int address, int Bit, char* Order);
typedef int (_stdcall *pCancelAllF)(int nport, int node);

typedef int (_stdcall *pSet)(int nport, int node, int address, int Bit, char* Order);
typedef int (_stdcall *pReSet)(int nport, int node, int address, int Bit, char* Order);
typedef int (_stdcall *pReadBit)(int nport, int node, int address, int Bit, int Count, char* Order, int* RxdBuffer);
typedef int (_stdcall *pReadDInt)(int nport, int node, int address, int Count,int* RxdBuffer);
typedef int (_stdcall *pReadFloat)(int nport, int node, int address, int Count, float* RxdBuffer);
typedef int (_stdcall *pWriteDInt)(int nport, int node, int address, int Count, int* TxdBuffer);
typedef int (_stdcall *pWriteFloat)(int nport, int node, int address, int Count, float* TxdBuffer);

typedef int (_stdcall *pBitBin)(int value, int Bitaddress);
typedef int (_stdcall *p32I_16h)(int value);
typedef int (_stdcall *p32I_16l)(int value);
typedef int (_stdcall *p16I_32I)(int valueH, int valueL);
typedef int (_stdcall *p32f_16h)(float value);
typedef int (_stdcall *p32f_16l)(float value);
typedef float (_stdcall *p16I_32f)(int valueH, int valueL);

2)、建立动态链接库的新函数名：(在cpp文件的头处声明)

pOpen mOpen;
pClose mClose;
pSetDelay mSetDelay;
pComTrue mComTrue;
pComWork mComWork;

pMS mMS;
pSC mSC;
pMM mMM;
pTS mTS;
pReadInt mReadInt;
pReadTc mReadTc;
pWriteInt mWriteInt;

pSetF mSetF;
pReSetF mReSetF;
pCancelF mCancelF;
pCancelAllF mCancelAllF;

pSet mSet;
pReSet mReSet;
pReadBit mReadBit;
pReadDInt mReadDInt;
pReadFloat mReadFloat;
pWriteDInt mWriteDInt;
pWriteFloat mWriteFloat;

pBitBin mBitBin;
p32I_16h m32I_16h;
p32I_16l m32I_16l;
p16I_32I m16I_32I;
p32f_16h m32f_16h;
p32f_16l m32f_16l;
p16I_32f m16I_32f;

3)、导入动态链接库，如例所示：(在cpp文件的OnInitDialog过程建立)：

hinstDLL = LoadLibrary("Omron_HostLink.dll");

4)、判断dll文件是否存在并声明并建立动态链接库中的函数与新函数名的对应关系，

如下：(在cpp文件的OnInitDialog过程建立)：

if (hinstDLL)
{
mOpen = (pOpen)GetProcAddress (hinstDLL,"OmronComOpen");
mClose = (pClose)GetProcAddress (hinstDLL,"OmronComClose");
mSetDelay = (pSetDelay)GetProcAddress (hinstDLL,"OmronSetDelay");
mComTrue = (pComTrue)GetProcAddress (hinstDLL,"OmronComTrue");
mComWork = (pComWork)GetProcAddress (hinstDLL,"OmronComWork");

mMS = (pMS)GetProcAddress (hinstDLL,"OmronMS");
mSC = (pSC)GetProcAddress (hinstDLL,"OmronSC");
mMM = (pMM)GetProcAddress (hinstDLL,"OmronMM");
mTS= (pTS)GetProcAddress (hinstDLL,"OmronTS");
mReadInt = (pReadInt)GetProcAddress (hinstDLL,"OmronReadInt");
mReadTc = (pReadTc)GetProcAddress (hinstDLL,"OmronReadTc");
mWriteInt = (pWriteInt)GetProcAddress (hinstDLL,"OmronWriteInt");

mSetF = (pSetF)GetProcAddress (hinstDLL,"OmronSetF");
mReSetF = (pReSetF)GetProcAddress (hinstDLL,"OmronReSetF");
mCancelF = (pCancelF)GetProcAddress (hinstDLL,"OmronCancelF");
mCancelAllF = (pCancelAllF)GetProcAddress (hinstDLL,"OmronCancelAllF");

mSet = (pSet)GetProcAddress (hinstDLL,"OmronSet");
mReSet = (pReSet)GetProcAddress (hinstDLL,"OmronReSet");
mReadBit = (pReadBit)GetProcAddress (hinstDLL,"OmronReadBit");
mReadDInt = (pReadDInt)GetProcAddress (hinstDLL,"OmronReadDInt");
mReadFloat = (pReadFloat)GetProcAddress (hinstDLL,"OmronReadFloat");
mWriteDInt = (pWriteDInt)GetProcAddress (hinstDLL,"OmronWriteDInt");
mWriteFloat = (pWriteFloat)GetProcAddress (hinstDLL,"OmronWriteFloat");

mBitBin = (pBitBin)GetProcAddress (hinstDLL,"DecBitBin");
m32I_16h = (p32I_16h)GetProcAddress (hinstDLL,"Int32ToInt_16h");
m32I_16l = (p32I_16l)GetProcAddress (hinstDLL,"Int32ToInt_16l");
m16I_32I= (p16I_32I)GetProcAddress (hinstDLL,"Int16ToInt32");
m32f_16h = (p32f_16h)GetProcAddress (hinstDLL,"Float32ToInt_16h");
m32f_16l = (p32f_16l)GetProcAddress (hinstDLL,"Float32ToInt_16l");
m16I_32f= (p16I_32f)GetProcAddress (hinstDLL,"Int16ToFloat32");

AfxMessageBox("Omron_HostLink.dll已成功载入！");
}
else
{
AfxMessageBox("没找到Omron_HostLink.dll！");
SendMessage(WM_CLOSE);
}

注：双引号中为动态链接库中的原有函数名。


函数中用到了char*型参数，这里介绍下char*与Cstring的相互转换的函数：

(1)char*->CString

char* sz;
CString str;
str.Format("%s",sz); //可以用此函数将读取的值转成字符串

(2) CString -> char*

CString str;
char* sz = str.GetBuffer(0);//可将字符串转成char*给函数赋值


5）、当不再需要使用DLL时记得关闭串口及释放动态链接库，(在OnDestroy事件中释放)

if(hinstDLL)
{
int k = mComTrue(mnport);
if (k==1)
{
mClose(mnport);
}
FreeLibrary(hinstDLL);
}

上面的DLL使用要点也适用于其他各种windows标准DLL的VC调用。

当需要进行16位整数、32位整数、32位浮点数值进行混合读写时，所需拓展函数包括：

1)、DecBitBin 字整数的位抽取；

2)、Int32ToInt_16h 双字到字转换高位字；

3)、Int32ToInt_16l 双字到字转换低位字；

4)、Int16ToInt32 字到双字的转换；

5)、Float32ToInt_16h 浮点到字转换高位字；

6)、Float32ToInt_16l 浮点到字转换低位字；

7)、Int16ToFloat32 字到浮点的转换；

8)、介绍如何实现数据的混合读取和写入；

这里以VB程序为例叙述一下如何进行混合数据的读写。

混合数据的读写，一般都是与PLC的DM区元件的进行操作，因其他

元件区可能不一定支持32位整数及32位单精度浮点数。

这里PLC中DM0、DM1、DM4、DM5是16位整数元件，DM2是32位整数元件，DM6是32位单精度浮点元件

1、混合数据的读

Dim nodeI, addrI, ReadInt As Long
Dim buffer(1024) As Long ‘定义一个数据接收缓冲区 整型为1024，浮点型为256
Dim strreal As String
nodeI = Val(Combnode.Text) ‘取得PLC节点号
addrI = 0 ‘其实地址从DM0开始，DM0~DM7,8个寄存器值
ReadInt = OmronReadInt(ComPort, nodeI, addrI, 8, "DM", buffer(0)) ‘读取字元件值
If ReadInt = 8 Then
ReadText(0).Text = Trim(Str(buffer(0)))
ReadText(1).Text = Trim(Str(buffer(1)))
ReadText(2).Text = Trim(Str(Int16ToInt32(buffer(3), buffer(2)))) ‘DM2为32位整数元件
ReadText(3).Text = Trim(Str(buffer(4)))
ReadText(4).Text = Trim(Str(buffer(5)))
strreal = Trim(Str(Int16ToFloat32(buffer(7), buffer(6)))) ‘DM6为32位单精度浮点数元件
ReadText(5).Text = Format(strreal, "0.000")
End If

2、混合数据的写

Dim SendInt As Integer
Dim SendFloat As Single
Dim nodeI, addrI, addrBit, ReadInt, SendDint As Long
Dim nameplc As String
Dim buffer(1024) As Long ‘定义一个数据发送缓冲区 整型为1024，浮点型为256

‘将混合的数据转换成16位整数,数组
SendInt = Val(SendText(0).Text) ‘16位整数
buffer(0) = SendInt
SendInt = Val(SendText(1).Text) ‘16位整数
buffer(1) = SendInt
SendDint = Val(SendText(2).Text) ‘32位整数
buffer(2) = Int32ToInt_16l(SendDint)
buffer(3) = Int32ToInt_16h(SendDint)
SendInt = Val(SendText(3).Text) ‘16位整数
buffer(4) = SendInt
SendInt = Val(SendText(4).Text) ‘16位整数
buffer(5) = SendInt
SendFloat = Val(SendText(5).Text) ‘32位浮点数
buffer(6) = Float32ToInt_16l(SendFloat)
buffer(7) = Float32ToInt_16h(SendFloat)

Call OmronWriteInt(ComPort, nodeI, addrI, 8, "DM", buffer(0)) ‘按16位整数写入PLC

 

这是你写的dll吗,哪里可以下载,是不是要收费?我一直用VC,能不能写个VC串口编程使用范例.

这个。。。