Hi,
I want to generate two simultaneous analog outputs on a NI USB-6211.
I'm using NI-DAQmx Base for Mac OS X v.3.4.0 in a Xcode 3.1.3 environment (in C) on a MacOSX 10.5 (intel). -- No Labview.
Using the provided example (contGeneration.c), I can get a sine wave with: "Dev1/ao0"
I do not get any ouput when creating a single task for "Dev1/ao0:1" as suggested in many threads on the subject.
How can I get the two analog outputs to work at the same time? Ideally, it would allow for the output to be different, and synchronized.
Thank you,
RT1
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// Task parameters
int32 error = 0;
TaskHandle taskHandle = 0;
int32 i = 0;
char errBuff[2048]={'\0'};
time_t startTime;
bool32 done=0;
// Channel parameters
char chan[] = "Dev1/ao0:1"; //****************************************************************
float64 min = -10.0;
float64 max = 10.0;
// Timing parameters
#define bufferSize 512
uInt64 samplesPerChan = bufferSize;
float64 sampleRate = 10000.0;
// Data write parameters
float64 data[bufferSize];
int32 pointsWritten;
float64 timeout = 10.0;
for(;i<bufferSize;i++)
data[i] = 9.95*sin((double)i*2.0*PI/(double)bufferSize);
DAQmxErrChk (DAQmxBaseCreateTask("",&taskHandle));
DAQmxErrChk (DAQmxBaseCreateAOVoltageChan(taskHandle,chan,"",min,max,DAQmx_Val_Volts,NULL));
DAQmxErrChk (DAQmxBaseCfgSampClkTiming(taskHandle,"",sampleRate,DAQmx_Val_Rising,DAQmx_Val_ContSamps,samplesPerChan));
DAQmxErrChk (DAQmxBaseWriteAnalogF64(taskHandle,samplesPerChan,0,timeout,DAQmx_Val_GroupByChannel,data,&pointsWritten,NULL));
DAQmxErrChk (DAQmxBaseStartTask(taskHandle));
gRunning = 1;
// The loop will quit after 10 seconds
startTime = time(NULL);
while( gRunning && !done && time(NULL)<startTime+10 ) {
DAQmxErrChk (DAQmxBaseIsTaskDone(taskHandle,&done));
if( !done )
usleep(100000);
}
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);
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