Hardware Digital Trigger using DAQ Assistant Express VI

[John_Essick]

I would like to write a digitally triggered oscilloscope LabVIEW program for a myDAQ using the DAQmx Express VI DAQ Assistant. However, when using the Triggering tab in DAQ Assistant, the Digital Trigger option is greyed out. Is it possible to hardware trigger a myDAQ, possibly using a Digital I/O line?

[Jake_G]

Hey John,

It may be greyed out because you may have the Generation Mode set to 1 Sample (On Demand).  If you check in Configuration Tab under Timing Settings, try setting the Generation Mode to 1 Sample (HW Timed), N Samples, or Continuous Samples.

Jake

[John_Essick]

Jake--

 I have N Samples selected in DAQ Assistant and am not able to choose Digital Edge Triggering without getting an error message. I was hoping there was some work-around for this, possibly by using the digital inputs. Thanks for your help.

John

[T-REX$]

Hi John,

Personally I would avoid using the daq assistant for this type of work. This article should help get you started with manually triggering the device.

[John_Essick]

TJG--

 This summer, I'm running a workshop for instructional lab instructors based on a LabVIEW book I wrote which implements the DAQ Assistant in earlier chapter (DAQmx is covered in later chapters). Many of the participants are looking for low-cost ways to include LabVIEW in their lab courses, so I'm including work with the myDAQ during the workshop. MyDAQ does everything I need, except seems to lack hardware triggering of the analog input operation (unfortunately). 

[T-REX$]

Hi John,

I just went and grabbed a myDAQ to verify this behavior, and creating a digital trigger on the myDAQ is indeed impossible through the DAQ Assistant. I get the following error:

   Error -200077 occurred at DAQ Assistant
   Possible Reason(s):

   Requested value is not a supported value for this property.

   Property: Start.TrigType
   You Have Requested: Digital Edge
   You Can Select: None

This is because of the limited functionality of the myDAQ, which is unfortunate... Sorry I couldn't be of more help

[John_Essick]

TJG--

 Thanks for verifying with your unit. Hope digital triggering is included on future version of myDAQ