Change form of output signal without initializing new process of output signal

[_Pavel_]

Hello!

How to change form of output signal produced on the output channel without initializing new process of output signal?

Thanks 

Message Edited by _Pavel_ on 10-28-2009 05:21 PM

[Christian Mergl]

Hey,

It depends on the hardware. If you are using something from NI I would suggest to post again a bit more specific in the hardware forums.

Christian

[_Pavel_]

I'm use PCI 6221. I think the task consists in correct installation and tuning DAQmx that becomes program.

Thanks 

[Christian Mergl]

Could you please be a bit more specific?

- are you working with LabVIEW?

- what exactly is the problem?

- continous/finite generation?

Thanks,

Christian

[_Pavel_]

I'm working with LabView 8.5.1.

I have periodic TTL impulse with constant frequency – signal to start , which I'm used to start data acquisition (PCI-6251)and generation signal (PCI-6221).

When TTL signal a detection, necessary generation some analog signal (PCI-6221) and acquisition other analog signal (PCI-6251).  Then wait following TTL signal.

At this moment I write the part of the program which is responsible for data acquisition. Function retriggering (In examples C:\ProgramFiles\National Instruments\LabVIEW8.5\examples\DAQmx\Synchronization\Multi-Function.llb\Multi-Function-CtrRetrigg Pulse Train Generation for AI Sample Clock.vi) is used. This function necessary,because we start data acquisition each time on arrival TTL impulse, andrepeated creation of the virtual channel of data acquisition with the newtrigger spend a lot of time.

The problem consists in the following. Generation of the data from other card should occur on the same impulse TTL as for the data acquisition card and then generation zero value.

How I can realize it? I planned to change the form of an impulse of generation when detected TTL an impulse, without reinitialize process.

[Christian Mergl]

You allready got an answer to this question here: http://forums.ni.com/ni/board/message?board.id=170&message.id=451576#M451576

Christian

[_Pavel_]

Thanks!

But this message I write about other problem.

If I use this program http://zone.ni.com/devzone/cda/epd/p/id/5008, I spend a lot of time on Start and Stop Task, but time is very critical for my task. Whether I can make it somehow differently? 

[Christian Mergl · Accepted solution]

Yes, you can do the same without starting/stoping the task all the time.

Attached VI shows how to use retriggerable AO in the same way, using a counter as timebase for the AO.

Please notice that attached VI is using the same SubVI like the example you posted before.

Christian