Triggered, Multiple channel Analog Read: TIMEOUT

Hello,
I am trying to read multiple AI channels (differential), triggered with a DigitalStartLine. To trigger, I generate a Hi-Low pulse on the trigger line. My readanalogF64 function always returns a Timeout.
I have used the same trigger to write multiple AO channels and have succeeded but not with the read operations. I have also found that if I don't use a triggered read, I am able to do the read perfectly.
Following is the piece of code:
DAQmxErrChk (DAQmxCreateTask("",&ADC_taskHandle));
DAQmxErrChk (DAQmxCreateAIVoltageChan (ADC_taskHandle, "Dev1/ai0:7", "", DAQmx_Val_Diff, 0, 10, DAQmx_Val_Volts, NULL));
DAQmxErrChk (DAQmxCfgSampClkTiming (ADC_taskHandle, "", 1000, DAQmx_Val_Falling, DAQmx_Val_FiniteSamps, 1000));
DAQmxErrChk (DAQmxCfgDigEdgeStartTrig (ADC_taskHandle, "/Dev1/PFI1", DAQmx_Val_Falling));
DAQmxErrChk (DAQmxStartTask (ADC_taskHandle));
DAQmxErrChk (DAQmxReadAnalogF64 (ADC_taskHandle, 1000, 10, DAQmx_Val_GroupByChannel,ADC_Data, 8000, &read, NULL));
DAQmxErrChk (DAQmxStopTask (ADC_taskHandle));
// To generate the Trigger pulse
for(i=1;i>=0;i--)
if(i==1)
singleBit_array[0]=1.0;
else
singleBit_array[0]=0.0;
DAQmxErrChk (DAQmxCreateTask ("", &taskHandle));
DAQmxErrChk (DAQmxCreateDOChan (taskHandle, "/Dev1/PFI0", "", DAQmx_Val_ChanPerLine));
DAQmxErrChk (DAQmxStartTask (taskHandle));
DAQmxErrChk (DAQmxWriteDigitalLines(taskHandle,1,0,10.0,DAQmx_Val_GroupByChannel,singleBit_array,NULL,NULL));
DAQmxErrChk (DAQmxStopTask (taskHandle));
The ERROR I receive is:
Function DAQmxReadAnalogF64: (return value == -200284 (0xfffcf1a4))
Some or all of the samples requested have not yet been acquired.
Property: DAQmx_Read_RelativeTo
Corresponding Value: DAQmx_Val_CurrReadPos
Property: DAQmx_Read_Offset
Corresponding Value: 0
Any suggestions would be a great help.
regards,
Dwivedi

Dwivedi,
Sorry it's taken me a while to get back to you, I've had a pretty hectic day here. However I was able to sit down this afternoon and write a C program which accopmlishes what you were trying to do with AO. I have NI-DAQmx 7.4 installed and was testing using a PCI-6259. My program was able to run without error. Here is my code:
TaskHandle aoTask;
int32 err = 0;
float64 dataArray[8192];
int32 sampsWritten = 0;
for(int i=0; i<8192;i++)
if((i%200) < 100)
dataArray[i] = 6;
else
dataArray[i] = -6;
err = DAQmxCreateTask("TestAOTask", &aoTask);
if(err != 0)
printf("Error Creating task... Error Code %d\n", err);
return 0;
err = DAQmxCreateAOVoltageChan(aoTask, "Dev1/ao0", "aoChan", -10.0, 10.0, DAQmx_Val_Volts, "");
if(err != 0)
printf("Error Creating channel... Error Code: %d\n", err);
return 0;
err = DAQmxCfgSampClkTiming(aoTask, "", 50000.0, DAQmx_Val_Falling, DAQmx_Val_ContSamps, 8192);
if(err != 0)
printf("Error configuring sample clock... Error code: %d\n", err);
return 0;
err = DAQmxCfgDigEdgeStartTrig (aoTask, "/Dev1/PFI0",DAQmx_Val_Falling);
err = DAQmxWriteAnalogF64(aoTask, 8192, false, 10.0, DAQmx_Val_GroupByChannel, dataArray, &sampsWritten, NULL);
if(err != 0)
printf("Error durring write... Error Code: %d\n", err);
return 0;
err = DAQmxStartTask(aoTask);
err = DAQmxStopTask(aoTask);
err = DAQmxClearTask(aoTask);
return 0;
Sorry, the text editor for this forum seems to insert an extra newline for every time I hit enter. About the only difference I found between your code an mine is that I wrote the data before starting the task (which is what I would recommend for AO. This will ensure that there is data available for the DAC's once the task is started). If you re-order your code in this way do you see a change of behavior?
Sorry again it took me this long. Please let me know how this works.
Dan

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