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Retriggable option in Traditional-DAQ...

Hi everyone,

My inconing signal is a 1Hz square pulse with +5V amplitude. I would
like to define a trigger that will be operated only on the rising time
of the inconing signal crossing a threshold. when the signal falls to
its 0V, the trigger must be stopped. And continue again when rising
above the threshold

I managed to do it, but the trigger starts on the rising time of the
signal but it does not stop on the falling part..

I understood that i need to do some sort of a retriggable option, but
exactly how? does anyone have a sample code?

i am usind traditional-DAQ in labview v7.1
my hardware is DAQPad 6070E series
Windows XP

Help is really really appriciated

Thanks!!!!!!

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Message 1 of 11
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Hello Molder,

Doing a search on our example programs I found this example:
Acquiring Analog Input Within a Specified Range of Values

As you can see, this is doing something very close (if I understand correctly) to what you mention. Thank you for posting your hardware and OS information since that takes out of the picture the newer driver DAQmx where your device is not supported.

Hope this example helps,
Gerardo O.
RF SW Engineering R&D
National Instruments
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Message 2 of 11
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Hi Gerardo,

just to better clarify what i wanted to do:

1. I have an analogue signal as input. its a 1Hz square pulse with Amplitude 5v.

2. This is the signal source that should hardtrigger an analogue output with my software-defined pulse pattern

3. The analogue output rate is not important, it should start when triggered to start and stopped when there is no trigger

Does it clarify things?

Regarding your AI example

The example you've attached is for AI reading not for AO, but i tried it and it did not showed anything on the graph..

let me see that i got things right:

1. I have hardwired the same pulse from (1) above to PFI0

2. I have wrote PFI0 as the trigger source

3. AI1 as the AI channel to display the triggered acquire data

Was i correct?

Thanks!

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Message 3 of 11
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Hi Molderon,

That explains a little more although I am not sure why we can't consider this square 0-5 volts signal as a digital one since it has all the TTL characteristics.

For this, you can use the shipping example "Cont Generation - E-series D-Trig.vi" and change the "trigger or gate condition" to "pause while gate is TTL high". I have tried this and works exactly as you want it.

If you insist on your analog signal, then it will need to route that to counters before is routed to the analog output part as Raajit is suggesting in your other post.
Please keep any further answer on this thread,

good luck,
Gerardo O.
RF SW Engineering R&D
National Instruments
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Message 4 of 11
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Hi,
 
I will follow your lead, and will use the Raajit thread. My mistake Re the dual thread.
 
Thanks for your help !
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Message 5 of 11
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Hi Molderon,

Keep the discussion here, Raajit and I will monitor it. Hope the lead takes you to the final solution.

Gerardo O.
RF SW Engineering R&D
National Instruments
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Message 6 of 11
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Hi Gerardo,
 
It was only after my post yesterday that i saw your your message. I will continue this lead ,per your request. in the meantime attached is my last message from yestareday, hope you guys can help
 
Hi raajit,

Finnaly it worked!! many thanks for your help!!

There is one last thing, though 🙂

it seems that following a period of time in which the AO writes its
pulse pattern (sometime it after 10 seconds, sometim eits after 15
minutes), suddenly an AO message appears:

error: 10800 at AO control
NI-Daq LV: The operation could not complete within the time limit.

The error occured between the AO start and AO wait


Any clue?

Cheers
 
 
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Message 7 of 11
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Hello Molderon,

Good news that is working! We wonder if it was the shipped example or the one on the other thread?

The error occured between the AO start and AO wait

You probably then meant to say "between AO Start and AO Write"
You can increase the timeout of this function to something higher in case the time calculated by the driver is not sufficient.

Good luck,
Gerardo O.
RF SW Engineering R&D
National Instruments
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Message 8 of 11
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Hi Gerardo,

to the best of my recollection, i belive that on one of the posts, Raajit mentioned something about an example of Generate N updates Trig E series.

I am connecting my signal to the rising time of the PFI0 and there is a finite elements created by the AO start.

When using AO start in finite number of updates, it was written (in the help files of AO start) that AO wait should be used in order to make sure that the AO generation action is completed. hence i wrote that the error occured between AO start and AO wait

Thanks

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Message 9 of 11
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Hi Molderon,

Thanks for the name of the example. I left it running overnight (placing the while loop around it as Raajit told you) and did not get any errors. Did you add anything to this example?
Finally, you can change the value input called "Change Every N Updates" on the AO wait.vi to something higher.
Feel free to post any additional information that helps explain what is happening.
Gerardo O.
RF SW Engineering R&D
National Instruments
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