DAQmxCfgSampClkTiming Digital Output using 6229 PCI

[Germanherman49]

Hello,

i would like to write a number of samples. A sample should be aquired every second. For Example on port 0 should be written. Data should come out of a data array like:
data[10]={0x000f00f, 0xffffffff,......}. Each Element of this array should be written to the port 0 one time. So the complete session should last 10 seconds.

And the other way round i would like to do it, too. Do a sample from port 0, store it into an array, wait a second....

i tried it this way but it wouldn't work:


    uInt32      data[2]={0x000f00f, 0xffffffff;...};       
    int32        written;

    DAQmxErrChk (DAQmxCreateTask("",&taskHandle));
    DAQmxErrChk (DAQmxCreateDOChan(taskHandle,"Dev1/port0","",DAQmx_Val_ChanForAllLines));
    DAQmxErrChk (DAQmxCfgSampClkTiming(taskHandle,"OnboardClock",1.0,DAQmx_Val_Rising,DAQmx_Val_FiniteSamps,10));

    /*********************************************/
    // DAQmx Start Code
    /*********************************************/
    DAQmxErrChk (DAQmxStartTask(taskHandle));

    /*********************************************/
    // DAQmx Write Code
    /*********************************************/
    DAQmxErrChk (DAQmxWriteDigitalU32(taskHandle,10,1,10.0,DAQmx_Val_GroupByChannel,&data,&written,NULL));


Documentation says if i want to use the internal clock of the device i should use OnboardClock or NULL. Both doesn't work.


Thanks forward for every information
Greetings
Andreas

[MarkGrot]

You are seeing an error because digital tasks on M-Series do not support an internal sample clock.  Don't worry, you can still accomplish what you are trying to do.  You will need to select a sample clock source since the digital system cannot create one for you.  The easiest way to do this is to use a counter task to create a pulse train and use that as your clock.  Then you would configure your timing to be something like:

DAQmxErrChk (DAQmxCfgSampClkTiming(taskHandle,"/Dev1/Ctr0InternalOutput",1.0,DAQmx_Val_Rising,DAQmx_Val_FiniteSamps,10));