Hi,
I am trying to use a PCI6182 M Series board with DAQmx Base under
Mandrake Linux 10.1 Official (everything is configured OK and examples
run fine)
I am trying to obtain synchronous AI and AO (continuous AO single channel and finite samples AI single channel)
DAQmx complains, and exits with an error, when an AI operation is
started while the AO operation is running, with the following message:
DAQmxBase Error: RLP Invoke Node <err>The DMA Channel is in the
wrong state. The DMA Channel may need to be
<b>Reset</b>. Or you may have specified an
<b>invalid DMA Mode</b>, or a DMA Mode which has not been
implemented yet.
I have read on the DAQmx Base documentation that it should be possible
to run concurrent tasks as long as they operate on different channels
or, if they operate on the same channel, as long as one task is an
output and the other is an input.
Apparently I am meeting this condition, but after several trials I am still not able to run the DAQ board as needed.
Does anyone know if it is possible at all to do continuous AO while performing AI under DAQmx Base - Linux ?
I am attaching at the end if this post the core of the code that I am
running as a test (it is basically the merge of AO and AO example
codes), and the output messages that result from it.
Thanks in advance for any help,
Regards,
Andrea.
// Create Write Task
printf ("Before creating write task\n");
DAQmxErrChk (DAQmxBaseCreateTask("",&taskHandleWr));
DAQmxErrChk (DAQmxBaseCreateAOVoltageChan(taskHandleWr,chanWr,"",min,max,DAQmx_Val_Volts,NULL));
DAQmxErrChk (DAQmxBaseCfgSampClkTiming(taskHandleWr,
source,sampleRate,DAQmx_Val_Rising,DAQmx_Val_ContSamps,writeSamplesPerChan));
// Start a continuous writig task
printf ("Before istantiating write task\n");
DAQmxErrChk(DAQmxBaseWriteAnalogF64(taskHandleWr,writeSamplesPerChan,0,timeout,DAQmx_Val_GroupByChannel,writeData,&pointsWritten,NULL));
printf ("Before starting write task\n");
DAQmxErrChk (DAQmxBaseStartTask(taskHandleWr));
// Create Read Task
printf ("Before creating read task\n");
DAQmxErrChk (DAQmxBaseCreateTask ("", &taskHandleRd));
DAQmxErrChk (DAQmxBaseCreateAIVoltageChan
(taskHandleRd, chanRd, "", DAQmx_Val_Cfg_Default, min, max,
DAQmx_Val_Volts, NULL));
DAQmxErrChk (DAQmxBaseCfgSampClkTiming
(taskHandleRd, source, sampleRate, DAQmx_Val_Rising,
DAQmx_Val_FiniteSamps, readSamplesPerChan));
// Start a concurrent read task
printf ("Before instantiating read task\n");
DAQmxErrChk (DAQmxBaseReadAnalogF64 (taskHandleRd,
pointsToRead, timeout, 0, readData, readBufferSize, &pointsRead,
NULL));
printf ("Before starting read task\n");
DAQmxErrChk (DAQmxBaseStartTask (taskHandleRd));
printf ("Acquired %d samples\n", pointsRead);
**********************************OUTPUT FROM PROGRAM******************************************
Before creating write task
Before istantiating write task
Before starting write task
Before creating read task
Before instantiating read task
DAQmxBase Error: RLP Invoke Node <err>The DMA Channel is in the
wrong state. The DMA Channel may need to be
<b>Reset</b>. Or you may have specified an
<b>invalid DMA Mode</b>, or a DMA Mode which has not been
implemented yet.
