Automated repeated recordings

[JMT_1931]

Hi there,

First time poster in this forum and a new user of this software.

NI-6210 DAQ monitors the analog line on AI0 input. This input sits at about 2.75 VDC above the ground, but occasionally can drop to about 2.5 VDC for a fraction of a second at a time. I have put together a circuit that detects the falling edge of the analog signal and triggers the DAQ's digital line (PFI0) with a 5V High pulse. DAQExpress can then record a single "occurrence" or "event". 

I am trying to make automated repeated recordings of multiple occurrences that can take place at random intervals (up to hours/days apart).  

Is there a way to do this in DAQExpress alone?

Screenshot attached for reference.

Thanks in advance.

[Dafrizzy]

Hi JMT,

Have you looked into how to automate data acquisition using the programming features of DAQExpress? I believe you should be able to programmatically export (record) the data when it drops to that 2.5 V level repeatedly over the course of hours/days. I think you will be limited to the constant recording, record for specified interval, or manually capture frame options if you use the basic DAQExpress features. 

We have some great getting started videos for programming in DAQExpress though. I have provided a link to them below.

"Programming Using DAQExpress": https://www.ni.com/en/shop/data-acquisition-and-control/application-software-for-data-acquisition-an...

Hope this helps!

[AvatarAang]

Hi,

I am assuming you have modified DAQExpress code? Are you willing to share what your code currently looks like to achieve this one-time triggering?

[JMT_1931]

Daniel,

I'd rather skip feeding the data continuously over the USB bus and into the PC for the purpose of identifying the drops by the DAQExpress software. 

OTOH, there is a 5V pulse generated externally and I 'd like to use it for (re)triggering the recordings (a few seconds at a time then stop).

In such arrangement, only the data in interest would be saved on the hard drive and the rest would be discarded thus reducing the possibility of the USB bus getting choked on a (rare?) occasion.

I am currently working with NI on the question of identifying a DAQ that might support multiple recordings.

NI USB 63xx perhaps?

Thanks.

Thanks!

[JMT_1931]

No, there is no modified code at this time, sorry.

[Dafrizzy]

You should be able to program it in DAQExpress to just have a loop that starts a task whenever there is a trigger and stops it after the acquisition has ended then loops back to wait for another trigger. A USB 63xx would probably work fine for that.

[JMT_1931]

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@Dafrizzy wrote:

You should be able to program it in DAQExpress to just have a loop that starts a task whenever there is a trigger and stops it after the acquisition has ended then loops back to wait for another trigger. A USB 63xx would probably work fine for that.

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Attempting to resurrect the old thread.

The project update: USB-6210 DAQ, external 5V trigger signal fed to PFI0. Able to grab 5 seconds worth of analog data (AI0 referenced single-ended) at the rate of 1000 Samples/sec on the trigger's falling edge. Every time the trigger occurs, the DAQ Express updates the trace - this part works OK.

Next step is to automatically record the frame every time the triggering occurs, but I do not know how.

Attached are the screenshot and the zipped project files.

TIA!

[PahlM]

Hello JMT,

Could you please explain what you mean by record the frame? 

Also, are you using LabVIEW NXG?

If you would like to explore how to save a report in Microsoft, such as excel, we have great tutorials here:

https://www.ni.com/en/shop/labview/data-storage-reporting-labview.html

[JMT_1931]

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@PahlM wrote:

Could you please explain what you mean by record the frame? 

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Please refer to the screengrab picture in my previous post (yellow-highlighted area)

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@PahlM wrote:

Also, are you using LabVIEW NXG?

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No, I am using DAQExpress.

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@PahlM wrote:

If you would like to explore how to save a report in Microsoft, such as excel, we have great tutorials here:

http://www.ni.com/tutorial/3201/en/ 

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 I'll take a look.

Thanks, PahlM.