Digital Start Trigger Not Working With Simulated Devices

Updated Jun 28, 2018

Reported In

Driver

  • NI-DAQmx

Issue Details

I would like to acquire data from multiple tasks (for example, a linear position task and an analog input task) using a NI-DAQmx device; to test my application, I created a simulated NI-DAQmx device. Since the two signals should be synchronized, I configured a common external digital trigger, using DAQmx Start Trigger (Digital Edge).vi and selecting one of the available PFI lines as the trigger source.
However, when I start my application, the tasks immediately start to acquire data even if no digital edge actually occurs on the PFI line, while I would have expected the task to wait for the external trigger.

Why is digital start trigger not working when using a NI-DAQmx simulated device?
 

Solution

This behaviour is expected when using NI-DAQmx simulated devices, as simulated devices do not support or simulate triggering. All data will be returned immediately, even if an external trigger was configured. 

This is one of the limitations of NI-DAQmx simulated devices.
 

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