PCI-6115 external conversion problem

[MCorto]

Hello

I have following problem with 6115 card:

When i try to collect samples using external TTL generator everything is ine until I lower the signal frequency from generator to less than 2.5kHz. Then the sampling timing goes out the window. Does anyone had same problem and solved it somehow? I'd be gratefull for any suggestions.

Best Regards

Maciej

[MCorto]

P.S

I'm using following code:

    i16 iStatus = 0;
    i16 iRetVal = 0;
    i16 iDevice = 1;
    i16 iChan = Channel;
    i16 iStartTrig = 0;
    i16 iExtConv = 2;
    i16 iGain = 1;
    u32 ulCount = il_prob;
    f64 dGainAdjust = 1.0;
    f64 dOffset = 0.0;
    i16 iSampTB = 0;
    u16 uSampInt = 0;
    i16 iDAQstopped = 0;
    u32 ulRetrieved = 0;
    i16 iIgnoreWarning = 0;
    i16 iYieldON = 1;

    iRetVal = NIDAQErrorHandler(iStatus, "Select_Signal",
     iIgnoreWarning);

    iStatus = DAQ_Config(iDevice, iStartTrig, iExtConv);

    iRetVal = NIDAQErrorHandler(iStatus, "DAQ_Config",
     iIgnoreWarning);

    iStatus = DAQ_Start(iDevice, iChan, iGain, piBuffer, ulCount,
     iSampTB, uSampInt);

    iRetVal = NIDAQErrorHandler(iStatus, "DAQ_Start", iIgnoreWarning);
   

    iRetVal = NIDAQErrorHandler(iStatus, "DAQ_Check", iIgnoreWarning);
   

    iStatus = DAQ_VScale(iDevice, iChan, iGain, dGainAdjust, dOffset,
     ulCount, piBuffer, pdVoltBuffer);

    iRetVal = NIDAQErrorHandler(iStatus, "DAQ_VScale",
     iIgnoreWarning);

    iStatus = DAQ_Config(iDevice, 0, 0);

    iStatus = Select_Signal(iDevice, ND_IN_CONVERT, ND_INTERNAL_TIMER,
     ND_LOW_TO_HIGH);

[WM_John_Weeks]

Note that the specs for the pci-6115 tell you that the minimum sampling rate is 20 kS/s.