NI-Scope examples

INTRODUCTION

National Instruments produce a wide range of 8-,12-,14,16-,24-bit Oscilloscopes/Digitizers cards in PCI, PCIe, PXI and PXIe form factor with sample rate up to 12.5Gs/s. [1]

This cards are supported by NI-Scope driver. Only Linux 32-bit and Windows 32/64 bit are supported.

NI Scope for Linux

Hardware are supported by Ni-Scope 3.1 for Linux (download). This driver works only on Linux distributions with kernel 2.6.x RHEL 5.x, 6.x, Scientific Linux 5.x, 6.x and some old for example Mandrake 10.1. Read readme file to find list of supported hardware.

To install NI-Scope 3.1 properly under these distributions make this trick

  Install NI-DAQmx 8.0.2 after NI-Scope.

(NI-DAQmx8.0.2 download)

To check device presents in your system type nilsdev in terminal. Output should be like this

  NI PXI-5122: "Dev2" 
  NI PXI-5122: "Dev1"

Two PXI-5122 cards are present in the system with aliases Dev1 and Dev2.

NI-Scope for Windows

Windows OSes are supported by latest NI-Scope 14.1 driver (download).

Read readme to find list of supported hardware.

Use NIMAX utility to setup device alias, for example Dev1.

Library documentation

Your can view or download latest documentation here [2]. Alternately NI-Scope installation copy it to your PC, for example in Linux PC /usr/local/natinst/niscope/doc.

PASCAL bindings

You can download bindings for your operation system from this forum thread [3].

To use it in your application copy bindings to your project directory and add niscope.pas to USES section.

Code Examples

There are some small differences between Pascal bindings for Windows and Linux - sometimes same function parameter is variable in Linux, but in Windows is a pointer, for example in Linux somefunction(sampleRate:double):longint; in Windows somefunction(sampleRate:Pdouble):longint;

Linux examples

Autosetuped acquisition

In this example by calling niScope_AutoSetup driver automatically try to setup acquisition parameters.

program autosetupacq;

{$mode objfpc}{$H+}

uses
  {$IFDEF UNIX}{$IFDEF UseCThreads}
  cthreads,
  {$ENDIF}{$ENDIF}
  Classes, niscope, visatype,sysutils
  { you can add units after this };
var
  resourceName:string='Dev1';
  vi:ViSession=VI_NULL;
  wfmNum:ViInt32;
  actualRecordLength:dword;
  actualSampleRate:viReal64;
  data:array of viReal64;
  channel:string = '0';
  wfmInfo:array of niScope_wfmInfo;
  i:longint;
procedure CheckError(AErrorCode: ViStatus; Avi: viSession);
var
  errorMessage:string='';
  bufferSize:ViStatus;
begin
  SetLength(errorMessage,MAX_ERROR_DESCRIPTION);
  if (AErrorCode<>VI_SUCCESS) then begin
    //due on unkown string length niScope_GetErrorMessage should call twice
    //get buffer size
    bufferSize:=niScope_GetError(Avi,@AErrorCode,0,@errorMessage[1]);
    //read error message
    SetLength(errorMessage,bufferSize);
    niScope_GetError(Avi,@AErrorCode,Length(errorMessage),@errorMessage[1]);
    writeln(errorMessage);
    if Avi<>VI_NULL then begin
       niScope_close(Avi);
    end;
    Halt;
  end;
 end;
begin
  //Init Session
  CheckError(niScope_init(PChar(@resourceName[1]),NISCOPE_VAL_FALSE,NISCOPE_VAL_FALSE,@vi),vi);
  writeln('Vi handler value (should be 1):' ,vi);
  //auto setup measurement
  CheckError(niScope_AutoSetup(vi),vi);
  //read the actual record length and number of waveforms
  //setuped by autosetup
  CheckError(niScope_ActualRecordLength(vi,@actualRecordLength),vi);
  CheckError(niScope_SampleRate(vi,@actualSampleRate),vi);
  CheckError(niScope_ActualNumWfms(vi,PChar(@channel[1]),@wfmNum),vi);

  //set buffer for data (lenght of data array)
  SetLength(data,actualRecordLength*wfmNum);
  SetLength(wfmInfo,wfmNum);

  CheckError(niScope_Read(vi,PChar(@channel[1]),5.0,actualRecordLength,@data[0],@wfmInfo[0]),vi);
  //shows first 10 samples
  writeln('----first ten samples of record------------------');
  for i:=Low(data) to Low(data)+9 do writeln('sample[',i,'] = ',data[i]:4:2);
  //show Info
  writeln('---------------------------------------------------');
  writeln('Record lenght: ',actualRecordLength);
  writeln('Sample rate: ',actualSampleRate);
  writeln('Number of waveforms: ',wfmNum);
  //show Info from wfmInfo record
  writeln('Actual samples: ',wfmInfo[0].actualSamples);
  writeln('X Increament: ',wfmInfo[0].xIncrement);
  writeln('Gain: ',wfmInfo[0].Gain);
  //close Session
  if vi<>VI_NULL then niScope_close(vi)
end.

Binary acquisition

Use an appropriate niScope_FetchBinary8 or niScope_FetchBinary16 or niScope_FetchBinary32 function passed to your card to get right signal samples.

program binaryacq;

{$mode objfpc}{$H+}

uses
  {$IFDEF UNIX}{$IFDEF UseCThreads}
  cthreads,
  {$ENDIF}{$ENDIF}
  Classes,niscope,visatype
  { you can add units after this };
 var
   error:ViStatus = VI_SUCCESS;
   vi:ViSession;
   //Variables setuped hardware
   resourceName:string = 'Dev1';
   channelName:string = '0,1';  //measurement channel(s)
   verticalRange:ViReal64 = 10;//measurement range -5 - 5 V
   verticalOffset:ViReal64 = 0.0;
   minSampleRate:ViReal64 = 2e5;
   minRecordLength:ViInt32 = 1000;
   binaryDataType:ViInt32;
   numWaveform:ViInt32;
   actualRecordLength:ViInt32;
   //Default values
   triggerType:ViInt32 = 0; //Immediate trigger
   triggerCoupling:ViInt32 = NISCOPE_VAL_DC;
   triggerSlope:ViInt32 = NISCOPE_VAL_POSITIVE;
   triggerLevel:ViReal64 = 0.0;
   triggerHoldoff:ViReal64 = 0.0;
   triggerDelay:ViReal64 = 0.0;
   triggerSource:string = '0';//nastavit kanal pro trigger
   refPosition:ViReal64 = 50.0;
   timeout:ViReal64 = 5.0;
   stop:ViInt32;
   i,j:ViInt32;

   wfmInfo:array of niScope_wfmInfo;
   scaledWfm:array of ViReal64;
   //NI-5122 is 14-bit digitizer
   binaryWfm:array of ViInt16;
procedure CheckError(AErrorCode: ViStatus; Avi: viSession);
var
  errorMessage:string='';
  bufferSize:ViStatus;
begin
  SetLength(errorMessage,MAX_ERROR_DESCRIPTION);
  if (AErrorCode<>VI_SUCCESS) then begin
    //due on unkown string length niScope_GetErrorMessage should call twice
    //get buffer size
    bufferSize:=niScope_GetError(Avi,@AErrorCode,0,@errorMessage[1]);
    //read error message
    SetLength(errorMessage,bufferSize);
    niScope_GetError(Avi,@AErrorCode,Length(errorMessage),@errorMessage[1]);
    writeln(errorMessage);
    if Avi<>VI_NULL then begin
       niScope_close(Avi);
    end;
    Halt;
  end;
 end;
begin
   //Open the NI_SCOPE instrument handler
   CheckError(niScope_init(Pchar(@resourceName[1]),NISCOPE_VAL_FALSE,NISCOPE_VAL_FALSE,@vi),vi);

   //Configure the vertical parameters
   CheckError(niScope_ConfigureVertical(vi,PChar(@channelName[1]),verticalRange,verticalOffset,NISCOPE_VAL_DC,1.0,NISCOPE_VAL_TRUE),vi);
   //Configure the horizontal parameters
   //one record

   CheckError(niScope_ConfigureHorizontalTiming(vi,minSampleRate,minRecordLength,refPosition,1,VI_TRUE),vi);
   //Configure the trigger

   if triggerType<>0  //Edge
     then CheckError(niScope_ConfigureTriggerEdge(vi,PChar(@triggerSource[1]),triggerLevel,triggerSlope,triggerCoupling,triggerHoldoff,triggerDelay),vi)
     else CheckError(niScope_ConfigureTriggerImmediate(vi),vi);

   //Get number of waveforms
   CheckError(niScope_ActualNumWfms(vi,PChar(@channelName[1]),@numWaveform),vi);

   //Get record length
   CheckError(niScope_ActualRecordLength(vi,@ActualRecordLength),vi);
   writeln('Record length: ',ActualRecordLength);

   //Set buffer for data and waveform Info
   SetLength(binaryWfm,ActualRecordLength*numWaveform);
   SetLength(scaledWfm,ActualRecordLength*numWaveform);
   SetLength(wfmInfo,numWaveform);

   //signal acquisition  1 record
   stop:=NISCOPE_VAL_FALSE;
   while stop<>NISCOPE_VAL_TRUE do begin
     CheckError(niScope_InitiateAcquisition(vi),vi);
     CheckError(niScope_FetchBinary16(vi,PChar(@channelName[1]),timeout,actualRecordLength,@binaryWfm[0],@wfmInfo[0]),vi);
     stop:=NISCOPE_VAL_TRUE;
   end;
   niScope_Close(vi);
   //calculate scaled data from binary data
   for i:=0 to NumWaveform-1 do
     for j:=0 to ActualRecordLength-1 do scaledWfm[j+(i*ActualRecordLength-1)]:=binaryWfm[j+(i*ActualRecordLength-1)]*wfmInfo[i].Gain+wfmInfo[i].offset;

   for i:=0 to NumWaveform-1 do begin
     writeln('   Waveform channel   ',i+1);
     writeln('   First 10 samples ');
     writeln('----------------------');
     for j:=0 to 10 do writeln('value[',j,'] = ',scaledWfm[j+(i*ActualRecordLength-1)]:4:2);
     writeln('----------------------');
  end;
   writeln('program stoped');
end.

Windows examples

Autosetuped acquisition

In this example by calling niScope_AutoSetup driver automatically try to setup acquisition parameters.

program autosetupacq;

{$mode objfpc}{$H+}

uses
  {$IFDEF UNIX}{$IFDEF UseCThreads}
  cthreads,
  {$ENDIF}{$ENDIF}
  Classes, niscope, visatype,sysutils
  { you can add units after this };
var
  resourceName:string='Dev3';
  vi:ViSession=VI_NULL;
  wfmNum:ViInt32;
  actualRecordLength:dword;
  actualSampleRate:viReal64;
  data:array of viReal64;
  channel:string = '0';
  wfmInfo:array of niScope_wfmInfo;
  i:longint;
procedure CheckError(AErrorCode: ViStatus; Avi: viSession);
var
  errorMessage:string;
  bufferSize:ViStatus;
begin
  SetLength(errorMessage,MAX_ERROR_DESCRIPTION);
  if (AErrorCode<>VI_SUCCESS) then begin
    //should call twice because we don't know errorMessage length
    //get string length
    bufferSize:=niScope_GetErrorMessage(Avi,AErrorCode,0,@errorMessage[1]);
   //get Error message
    SetLength(errorMessage,bufferSize);
    niScope_GetErrorMessage(Avi,AErrorCode,Length(errorMessage),@errorMessage[1]);
    writeln(errorMessage);
    if Avi<>VI_NULL then begin
       niScope_close(Avi);
    end;
    Halt;
  end;
 end;
begin
  //Init Session
  CheckError(niScope_init(PChar(@resourceName[1]),NISCOPE_VAL_FALSE,NISCOPE_VAL_FALSE,@vi),vi);
  writeln('Vi handler value (should be 1):' ,vi);
  //auto setup measurement
  CheckError(niScope_AutoSetup(vi),vi);
  //read the actual record length and number of waveforms
  //setuped by autosetup
  CheckError(niScope_ActualRecordLength(vi,@actualRecordLength),vi);
  CheckError(niScope_SampleRate(vi,@actualSampleRate),vi);
  CheckError(niScope_ActualNumWfms(vi,PChar(@channel[1]),@wfmNum),vi);

  //set buffer for data (lenght of data array)
  SetLength(data,actualRecordLength*wfmNum);
  SetLength(wfmInfo,wfmNum);

  CheckError(niScope_Read(vi,PChar(@channel[1]),5.0,actualRecordLength,@data[0],@wfmInfo[0]),vi);
  //shows first 10 samples
  writeln('----first ten samples of record------------------');
  for i:=Low(data) to Low(data)+9 do writeln('sample[',i,'] = ',data[i]:4:2);
  //show Info
  writeln('---------------------------------------------------');
  writeln('Record lenght: ',actualRecordLength);
  writeln('Sample rate: ',actualSampleRate);
  writeln('Number of waveforms: ',wfmNum);
  //show Info from wfmInfo record
  writeln('Actual samples: ',wfmInfo[0].actualSamples);
  writeln('X Increament: ',wfmInfo[0].xIncrement);
  writeln('Gain: ',wfmInfo[0].Gain);
  //close Session
  if vi<>VI_NULL then niScope_close(vi)
end.

Binary acquisition

Use an appropriate niScope_FetchBinary8 or niScope_FetchBinary16 or niScope_FetchBinary32 function passed to your card to get right signal samples.

program binaryacq;
 
{$mode objfpc}{$H+}
 
uses
  {$IFDEF UNIX}{$IFDEF UseCThreads}
  cthreads,
  {$ENDIF}{$ENDIF}
  Classes,niscope,visatype
  { you can add units after this };
 var
   error:ViStatus = VI_SUCCESS;
   vi:ViSession;
   //Variables setuped hardware
   resourceName:string = 'Dev1';
   channelName:string = '0,1';  //measurement channel(s)
   verticalRange:ViReal64 = 10;//measurement range -5 - 5 V
   verticalOffset:ViReal64 = 0.0;
   minSampleRate:ViReal64 = 2e5;
   minRecordLength:ViInt32 = 1000;
   binaryDataType:ViInt32;
   numWaveform:ViInt32;
   actualRecordLength:ViInt32;
   //Default values
   triggerType:ViInt32 = 0; //Immediate trigger
   triggerCoupling:ViInt32 = NISCOPE_VAL_DC;
   triggerSlope:ViInt32 = NISCOPE_VAL_POSITIVE;
   triggerLevel:ViReal64 = 0.0;
   triggerHoldoff:ViReal64 = 0.0;
   triggerDelay:ViReal64 = 0.0;
   triggerSource:string = '0';//nastavit kanal pro trigger
   refPosition:ViReal64 = 50.0;
   timeout:ViReal64 = 5.0;
   stop:ViInt32;
   i,j:ViInt32;
 
   wfmInfo:array of niScope_wfmInfo;
   scaledWfm:array of ViReal64;
   //NI-5122 is 14-bit digitizer
   binaryWfm:array of ViInt16;
procedure CheckError(AErrorCode: ViStatus; Avi: viSession);
var
  errorMessage:string='';
  bufferSize:ViStatus;
begin
  SetLength(errorMessage,MAX_ERROR_DESCRIPTION);
  if (AErrorCode<>VI_SUCCESS) then begin
    //due on unkown string length niScope_GetErrorMessage should call twice
    //get buffer size
    bufferSize:=niScope_GetError(Avi,@AErrorCode,0,@errorMessage[1]);
    //read error message
    SetLength(errorMessage,bufferSize);
    niScope_GetError(Avi,@AErrorCode,Length(errorMessage),@errorMessage[1]);
    writeln(errorMessage);
    if Avi<>VI_NULL then begin
       niScope_close(Avi);
    end;
    Halt;
  end;
 end;
begin
   //Open the NI_SCOPE instrument handler
   CheckError(niScope_init(Pchar(@resourceName[1]),NISCOPE_VAL_FALSE,NISCOPE_VAL_FALSE,@vi),vi);
 
   //Configure the vertical parameters
   CheckError(niScope_ConfigureVertical(vi,PChar(@channelName[1]),verticalRange,verticalOffset,NISCOPE_VAL_DC,1.0,NISCOPE_VAL_TRUE),vi);
   //Configure the horizontal parameters
   //one record
 
   CheckError(niScope_ConfigureHorizontalTiming(vi,minSampleRate,minRecordLength,refPosition,1,VI_TRUE),vi);
   //Configure the trigger
 
   if triggerType<>0  //Edge
     then CheckError(niScope_ConfigureTriggerEdge(vi,PChar(@triggerSource[1]),triggerLevel,triggerSlope,triggerCoupling,triggerHoldoff,triggerDelay),vi)
     else CheckError(niScope_ConfigureTriggerImmediate(vi),vi);
 
   //Get number of waveforms
   CheckError(niScope_ActualNumWfms(vi,PChar(@channelName[1]),@numWaveform),vi);
 
   //Get record length
   CheckError(niScope_ActualRecordLength(vi,@ActualRecordLength),vi);
   writeln('Record length: ',ActualRecordLength);
 
   //Set buffer for data and waveform Info
   SetLength(binaryWfm,ActualRecordLength*numWaveform);
   SetLength(scaledWfm,ActualRecordLength*numWaveform);
   SetLength(wfmInfo,numWaveform);
 
   //signal acquisition  1 record
   stop:=NISCOPE_VAL_FALSE;
   while stop<>NISCOPE_VAL_TRUE do begin
     CheckError(niScope_InitiateAcquisition(vi),vi);
     CheckError(niScope_FetchBinary16(vi,PChar(@channelName[1]),timeout,actualRecordLength,@binaryWfm[0],@wfmInfo[0]),vi);
     stop:=NISCOPE_VAL_TRUE;
   end;
   niScope_Close(vi);
   //calculate scaled data from binary data
   for i:=0 to NumWaveform-1 do
     for j:=0 to ActualRecordLength-1 do scaledWfm[j+(i*ActualRecordLength-1)]:=binaryWfm[j+(i*ActualRecordLength-1)]*wfmInfo[i].Gain+wfmInfo[i].offset;
 
   for i:=0 to NumWaveform-1 do begin
     writeln('   Waveform channel   ',i+1);
     writeln('   First 10 samples ');
     writeln('----------------------');
     for j:=0 to 10 do writeln('value[',j,'] = ',scaledWfm[j+(i*ActualRecordLength-1)]:4:2);
     writeln('----------------------');
  end;
   writeln('program stoped');
end.

TESTED HARDWARE

• NI PXI-5122 tested successfully under Windows7 32-bit and Scientific Linux 6.x 32-bit.