PauseTrigger event

[joemg]

I am using a USB-6351 with MeasurementStudio 2013 running on Windows7.  I am generating a pulse train

on ctr0 and using PFI0 as a pause trigger.  Everything works fine.  When the digital input goes high the pulse train stops.  If I clear the digital input the pulse trains resumes as expected.

I am trying to figure out how to get an event when the trigger occurs so i can stop and dispose of the pulse train task.  As near as I can determine DigitalChangeDetection events are not supported on this device and the Done event does not occur on pause.

I found an example where they were using a timer to check for IsDone but I could not make that work with a pause trigger.

Suggestions?

[magpie15]

Here is a list of all of the text based NI-DAQmx example programs. There is a Counter Digital Events - Pause Trigger that may be helpful.

http://www.ni.com/example/6999/en/

[joemg]

Unfortunately no.  I am already using a hardward trigger (digital input going high) to pause the pulse generation.  I am needing a software event to let me know when the pulse generation pauses.  The syntax is confusing.  The digital input going high is an "event" that pauses pulse generation.  I need something similar to the "IsDone" software event that gets sent to an event handler when the pulse generation first pauses.

[magpie15 · Accepted solution]

DigitalChangeDetection should do what you want, and your device does support it. I have included a link to a tutorial on it, as well as the manual page and another helpful page on events and callbacks.

http://www.ni.com/tutorial/4102/en/

http://zone.ni.com/reference/en-XX/help/370473H-01/mstudiowebhelp/html/bf8f7d1e/

http://zone.ni.com/reference/en-XX/help/370473H-01/mstudiowebhelp/html/eventscallbacksthreadsafety/

[joemg]

Pulse genration is an output task.  The digital pause is a digital input.  I have been trying without success to find a way to associate a digital change event with the pause digital input of the pulse generation task.

As a kludge I have setup another timer to use the pause event as a timing source.  This approach was mentioned in another exchange on this message board.

Here's my code 

leftLimitCheck = new Task();
leftLimitCheck.CIChannels.CreateCountEdgesChannel("/Dev1/ctr1", "checkLeft", CICountEdgesActiveEdge.Rising, 0, CICountEdgesCountDirection.Up);
leftLimitCheck.Timing.ConfigureSampleClock("/Dev1/pfi0", 1000, SampleClockActiveEdge.Rising, SampleQuantityMode.FiniteSamples, 1000);
leftLimitCheck.SampleClock += new SampleClockEventHandler(LeftLimitReachedEvent);
leftLimitCheck.Start();

This works but an event from the pulse generation task would be the proper solution in my opinion

[joemg · Accepted solution]

Pulse genration is an output task.  The digital pause is a digital input.  I have been trying without success to find a way to associate a digital change event with the pause digital input of the pulse generation task.

As a kludge I have setup another timer to use the pause event as a timing source.  This approach was mentioned in another exchange on this message board.

Here's my code 

leftLimitCheck = new Task();
     leftLimitCheck.CIChannels.CreateCountEdgesChannel("/Dev1/ctr1", "checkLeft",

     CICountEdgesActiveEdge.Rising, 0, CICountEdgesCountDirection.Up);
leftLimitCheck.Timing.ConfigureSampleClock("/Dev1/pfi0", 1000, SampleClockActiveEdge.Rising,

     SampleQuantityMode.FiniteSamples, 1000);
leftLimitCheck.SampleClock += new SampleClockEventHandler(LeftLimitReachedEvent);
leftLimitCheck.Start();

This works but an event from the pulse generation task would be the proper solution in my opinion