Error -200284: Samples Have Not Been Acquired

Updated Dec 5, 2019

Reported In

Software

  • LabVIEW

Driver

  • NI-DAQmx
  • NI-SCOPE

Issue Details

  • When I run my LabVIEW program using a DAQmx Read VI I get an error that says:

Error -200284 occurred at DAQmx Read (Polymorphic).vi
Possible reason(s):
Measurements: Some or all of the samples requested have not yet been acquired

 

Solution

The error was returned because the timeout occurred before all samples requested were received. The following are different ways to help you avoid this error:

Adjust the timeout value:
There is a timeout input for the DAQmx Read VI. The timeout specifies the amount of time in seconds to wait for samples to become available. Please refer to the DAQmx Help: DAQmx Read (VI) for more context.

If your sampling rate is low and/or your samples to read is high the time specified for the timeout may elapse, returning an error. To correct this, increase the timeout to accommodate the rate and the samples to read. In general, the timeout value should be larger than the number of samples to read divided by the sample rate.
 

Increase the sample rate:
The sample rate should be larger than the samples to read divided by the timeout. In a DAQ Assistant Express VI, you can configure this on the Configuration tab in Timing Settings >> Rate (Hz). For more context refer to the DAQmx Help: DAQmx Timing (VI).
 

Decrease the number of samples to read:
The number of samples to read should be less than the Sample Rate multiplied by the timeout. In a DAQ Assistant Express VI, you can configure this on the Configuration tab in Timing Settings >> Samples to Read.

Verify that the start trigger is configured correctly:
There are two options for triggering:
  • One is where the trigger is coming on a PFI/RTSI/Trig line. Verify that the trigger is operational and sending its signal properly through the hardware. Next, verify that the hardware can support the line on which the trigger is being sent. Finally, verify that the software task is looking for that trigger on the proper line.
  • The second option is that the trigger is coming from another task on the same board. Verify that the hardware can support this operation. One task may provide a trigger and the second task configures a trigger with the source of the first task’s trigger. Verify that the software is programmed correctly

Verify that the external timing is configured correctly:
If the timing is coming from a different task or device, it is considered external timing. There are two options for external timing:
  • If the clock is coming in on a PFI/RTSI/Trig line, be sure: 
    • The clock is running.
    • The hardware can support the frequency of the clock being sent (bandwidth).
    • The hardware can support the internal route required from the external clock signal to the task timing source. 
    • The task is configured to use the external clock.
  • If the clock is coming from another task on the same board, verify that the hardware can support this operation. Configure the software to share the timing source between two DAQ tasks e.g. a counter task using an analog input task's sample clock.
Using a Counter Input Task:
If you're measuring a DC input signal please refer to Measure a Frequency of Zero Without Getting Timeout Error -200284.

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