External clock and hw trigger using USB-6210 on Linux with NI-DAQmx Base?

[ase-tom]

I've got two USB-6210 devices that I need to sync up so that they both gather data at exactly the same time. I've been told by NI support that I can send the clock out of Dev1/PFI4 and have both USB-6210s read the clock in via their own PFI0. I'd also like to trigger the data gathering for each device by sending a trigger out of Dev1/PFI6 and having both devices receive the trigger on PFI2.

All of my attempts to try this have been met with errors messages and my online searches seem to say that this isn't possible with USB devices on NI-DAQmx Base 3.4.0f2 on Linux.

I''ve tried using the ai example programs and those don't seem to work either for external clocks. Here's the code I tried:

#include "NIDAQmxBase.h"
#include <stdio.h>

#define DAQmxErrChk(functionCall) { if( DAQmxFailed(error=(functionCall)) ) { goto Error; } }

int main(void)
{
    // Task parameters
    int32       error = 0;
    TaskHandle  taskHandle = 0;
    char        errBuff[2048]={'\0'};
    int32       i;

    // Channel parameters
    char        chan[] = "Dev1/ai0";
    float64     min = -10.0;
    float64     max = 10.0;

    // Timing parameters
    char        clockSource[] = "/Dev1/PFI7";
    uInt64      samplesPerChan = 1000;
    float64     sampleRate = 10000.0;

    // Data read parameters
    #define     bufferSize (uInt32)1000
    float64     data[bufferSize];
    int32       pointsToRead = bufferSize;
    int32       pointsRead;
    float64     timeout = 10.0;


printf("Calling CreateTask...\n");
    DAQmxErrChk (DAQmxBaseCreateTask("",&taskHandle));
printf("Calling CreateAIVoltageChan...\n");
    DAQmxErrChk (DAQmxBaseCreateAIVoltageChan(taskHandle,chan,"",DAQmx_Val_Cfg_Default,min,max,DAQmx_Val_Volts,NULL));
printf("Calling CfgSampleClkTiming...\n");
    DAQmxErrChk (DAQmxBaseCfgSampClkTiming(taskHandle,clockSource,sampleRate,DAQmx_Val_Rising,DAQmx_Val_FiniteSamps,samplesPerChan));
printf("Calling StartTask...\n");
    DAQmxErrChk (DAQmxBaseStartTask(taskHandle));
printf("Calling ReadAnalogF64\n");
    DAQmxErrChk (DAQmxBaseReadAnalogF64(taskHandle,pointsToRead,timeout,DAQmx_Val_GroupByChannel,data,bufferSize,&pointsRead,NULL));

    printf ("Acquired %d samples\n", pointsRead);

    // Just print out the first 10 points
    for (i = 0; i < 10; ++i)
        printf ("data[%d] = %f\n", i, data[i]);

Error:
    if( DAQmxFailed(error) )
        DAQmxBaseGetExtendedErrorInfo(errBuff,2048);
    if(taskHandle != 0) {
        DAQmxBaseStopTask (taskHandle);
        DAQmxBaseClearTask (taskHandle);
    }
    if( DAQmxFailed(error) )
		printf ("DAQmxBase Error %d: %s\n", error, errBuff);
    return 0;
}

When I run the resulting program I see this:

  $ ./acquireNScans-ExtClk
  Calling CreateTask...
  Calling CreateAIVoltageChan...
  Calling CfgSampleClkTiming...
  DAQmxBase Error -89136: <err>Specified route cannot be satisfied, because the hardware does not support it.

So, can a clock and a trigger be imported via one of the PFI lines using a USB-6210 on Linux with NI-DAQmx Base? Can a clock and a trigger be exported via one of the PFI lines?

If so, does anyone have example code showing how to do this or can you at least tell me the names of the lines ('Dev1/PFI0' or whatever) so I can try again?

Any clues or suggestions would be helpful.

Thank you,

-Tom

[ase-tom · Accepted solution]

The clockSource in the example specifies an output channel rather than an input channel. Changing the source to "/Dev1/PFI0" solves the problem.

Please close this post.