用的是研华的PCL1800，我要实现的功能是AD通道接收DA通道发送的数据，AD通道和DA通道用一根导线连接起来，发送的是正弦，接收的应该和发送的一样吧 可是我发现接收的数据的幅值是发送的一半，当我发送的是个常值时，接收的数据几乎为零，这是为什么呀，请大家帮我看看程序到底哪出问题了，多谢了 #include <vcl.h> #pragma hdrstop #include "Unit1.h" #include "driver.h" #include "stdio.h" #include "math.h" #include "mmsystem.h" //--------------------------------------------------------------------------- #pragma package(smart_init) #pragma resource "*.dfm" TForm1 *Form1; LONG DriverHandle; // driver handle static PT_AOVoltageOut ptAOVoltageOut; // AOVoltageOut table static PT_AIVoltageIn ptAIVoltageIn; static PT_AIConfig ptAIConfig; LRESULT ErrCde; // return error code int DeviceNum; int DAChannel,ADChannel; static int step = 0; float backdata; FILE *DAfd,*ADfd; //--------------------------------------------------------------------------- __fastcall TForm1::TForm1(TComponent* Owner) : TForm(Owner) { TimerID = 0; } //--------------------------------------------------------------------------- void __fastcall TForm1::EditDeviceChange(TObject *Sender) { DeviceNum = StrToInt(EditDevice->Text); } //--------------------------------------------------------------------------- void __fastcall TForm1::EditDAChannelChange(TObject *Sender) { DAChannel = StrToInt(EditDAChannel->Text); } //--------------------------------------------------------------------------- void __fastcall TForm1::EditADChannelChange(TObject *Sender) { ADChannel = StrToInt(EditADChannel->Text); } //--------------------------------------------------------------------------- void __fastcall TForm1::FormCreate(TObject *Sender) { DAfd = fopen("DA.txt", "wt"); if(DAfd == NULL) MessageBox(NULL, "创建文件出错！", "出错信息", MB_OK); ADfd = fopen("AD.txt", "wt"); if(ADfd == NULL) MessageBox(NULL, "创建文件出错！", "出错信息", MB_OK); } //--------------------------------------------------------------------------- void __fastcall TForm1::ButStartClick(TObject *Sender) { ErrCde = DRV_DeviceOpen(DeviceNum,(LONG far *)&DriverHandle); if (ErrCde != SUCCESS) ErrorHandler(ErrCde); TimerID = timeSetEvent(10, 0, (LPTIMECALLBACK)TimeProc, 0, TIME_PERIODIC); if(TimerID ==0) ShowMessage("创建失败"); } //--------------------------------------------------------------------------- void __fastcall TForm1::ButStopClick(TObject *Sender) { DRV_DeviceClose((LONG far *)&DriverHandle); if(TimerID !=0) timeKillEvent(TimerID); Close(); } //--------------------------------------------------------------------------- void __fastcall TForm1::ErrorHandler(LRESULT dwErrCde) { //TODO: Add your source code here char szErrMsg[80]; DRV_GetErrorMessage(ErrCde,(LPSTR)szErrMsg); MessageBox(NULL,(LPCSTR)szErrMsg,"Driver Message",MB_OK); } void CALLBACK TForm1::TimeProc(UINT uID, UINT uMsg, DWORD dwUser, DWORD dw1, DWORD dw2) { float DAdata; DAdata = (float)(2.0 * sin(6.28318*(double)step/(double)100) + 2.0); ptAOVoltageOut.chan = DAChannel; ptAOVoltageOut.OutputValue = DAdata; fprintf(DAfd, "%f\n", ptAOVoltageOut.OutputValue); ErrCde = DRV_AOVoltageOut(DriverHandle,(LPT_AOVoltageOut)&ptAOVoltageOut); if(ErrCde != 0) Form1->ErrorHandler(ErrCde); ptAIConfig.DasGain = 0; ptAIConfig.DasChan = ADChannel; ErrCde = DRV_AIConfig(DriverHandle,(LPT_AIConfig)&ptAIConfig); if (ErrCde != SUCCESS) Form1->ErrorHandler(ErrCde); ptAIVoltageIn.chan = ADChannel; ptAIVoltageIn.gain = 0; ptAIVoltageIn.TrigMode = 0; ptAIVoltageIn.voltage = (FLOAT far *)&backdata; ErrCde = DRV_AIVoltageIn (DriverHandle,(LPT_AIVoltageIn)&ptAIVoltageIn); if(ErrCde != 0) Form1->ErrorHandler(ErrCde); fprintf(ADfd, "%f\n", backdata); step = step +10; }