I need help configuring NI-SCOPE 5122 for a continuous triggered acquisition

[Steve_G]

Hi,

I am using a 5122 digitizer card for triggered acquisition.  I have my external trigger source connected to the Trig input of the card, and my signal is connected to Channel 0.

I would like to set up my Labview software so that the card will wait for my external trigger (a one-time trigger) and then acquire data indefinitely.  I've looked at the Fetch Forever example, but that will stop the acquisition of pretrigger samples when the trigger occurs.  I've also tried setting up an Analog Edge Ref Trigger with the trigger source set to External TRIG, but it will not acquire indefinitely.

Thank you,

Steve

[Bueller]

Hi Steve,

Thank you for posting on the discussion forums. I would like to ask about few things.

What do you mean when you say that the Fetch Forever Example doesn't acquire indefinitely? In this example the Fetch VI is in a while loop, and it keeps on looping until you hit the stop button or an error occurs. Are you getting any error?

Also, it would help a lot if you can tell me what are the different set up parameters you are using.

Regards,

Faris A

[Steve_G]

Faris,

Thanks for helping me out with this one.

According to this article:  http://digital.ni.com/public.nsf/allkb/03726608568CB14786256F330071706D  the Fetch Forever will stop when a trigger occurs.  I have a trigger pulse going in to the Trig input on the PCI card, so I'm assuming that when my trigger occurs the pretrigger sampling will end, and the card will only acquire a finite number of samples (min record length) after the trigger.  I'd like the triggering to begin with the trigger pulse and continue indefinitely.

That article also mentions "niScope EX MultiRecord Fetch Forever VI" which I can't find anywhere (on my computer or the internet).

I am using this card for two types of acquisitions:

1.  Triggered acquisition of a finite number of points - multi-record.  This works great.  I Initialize the Scope; my Vertical parameters are vertical range of 20, and to acquire from Channel 0; my Horizontal parameters are Number of Records set to 200, minimum sample rate of 1E7, reference position is 0, min record length is 75; I Configure the trigger using Analog Edge Ref Trigger with Trigger Source set to External TRIG.  Then I Initiate the Acquisition and it acquires all of the data.

2.  Triggered acquisition of indefnite number of points.  This is the one I'm having trouble with.  There will be a single trigger.

I hope this is the information you needed.

Steve

[Bueller]

Steve,

Please check the following Example. It uses a digital trigger to continously fetch forever.

Let me know if you have mor questions.

Regards,

Faris

[jheersink]

Hi Steve,

I have a similar problem (though with a 5922 board). Were you able to find a solution? Using the digital arm trigger is of course not really different from using the sotware trigger.

Thanks

Joel