PXIe-6537 Stopping waveform generation

Hi all,

I am using a NI PXIe-6537 50MHz DIO card in a PXIe-1071 chassis. I have been assuming that the 50MHz speed quoted is the maximum sample generation speed.

Using the 'generate waveform' functionality of DAQmx I have been attempting to generate a waveform at a variety of speeds, however above 3MHz the 'Active' light on the card goes red and generation does fails to start (viewed on oscilloscope). At lower speeds of about 2.36MHz the generation starts as expected but then cuts out in the manner described above.

Using dotNET 4.0 with DAQmx 15.1:

double rate = 3;// MHz

rate *= 1000000; //

int sampleCount = 1;

int signalCount = 1;

data = newDigitalWaveform(sampleCount, signalCount);

byte[] dataSamples = newbyte[] { 255, 0, 255, 0, 255, 0, 255, 0, 255, 0, 255, 0, 255, 0 };

data = DigitalWaveform.FromPort(dataSamples);

wfWrite = newTask();

wfWrite.DOChannels.CreateChannel("PXI1Slot3/port0/line0:7", "", ChannelLineGrouping.OneChannelForAllLines);

wfWrite.Timing.ConfigureSampleClock("", rate, SampleClockActiveEdge.Rising, SampleQuantityMode.ContinuousSamples);

writer = newDigitalSingleChannelWriter(wfWrite.Stream);

writer.WriteWaveform(false, data);

wfWrite.Start();

Have I missed something?

Thanks,

jh16g15