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NI-scope PCI-5124 with 2 triggers

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I would like to ask about the start and reference trigger with PCI-5124.

I found an sample VI on the following link, however it doesn't work as I expected.




The VI "start_and_reference_trigger.vi" can detect both start and reference trigger in my system and they start data acquisition.

It starts data acquisition when both start and reference triggers are input.


However what I would like to do is:

 1. Sampling rate at 200MHz with record length 1500 with one channel.

 2. Receive the start trigger (i.e. 50Hz)

 3. Receive the reference trigger (i.e. 50kHz)

 4. For every reference trigger, I would like to acquire the data, i.e. acquiring 1500 data for each 100 reference trigger (not with the combination with the start trigger)


Start trigger: _|^|_________________________________________


Ref   trigger:______|__|__|__|__|__|__|__|__|__|__|__|__|__|__|____

                                 ^    ^    ^    ^   ^   ^   ^   ^    ^    ^   ^    ^    ^   ^  

                                 trigger timings that I would like to acquire


Trigger channels that I'm using are:

 Start trigger:  PFI 0

 Ref trigger:    PFI 1


With the sample VI "start_and...", I found that it acquires when both start and reference trigger comes and the data acquisition is only after the one reference trigger. 

I hope my explanation is understandable and I can have a solution soon.

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Message 1 of 12
Accepted by topic author Tom 1225

Hi Tom,


This example configures a start and reference trigger, but only for a single record. It is inside a loop so it will continue to require a start and reference trigger for every record. Based on your description of the problem, you would like to perform a standard multi-record acquisition of 100 records, but you would like to implement a start trigger at the beginning of the acquisition. To do this, you can simply open the shipping example "niScope EX  Multi Record.vi" which can be found in the LabVIEW Example Finder or by navigating from your Windows Start menu to Programs » National Instruments » NI-SCOPE » Example. You will need to add the property node to set your Start Trigger source to be PFI 0, but other than that, it should work fine. I went ahead and created a simplified version with the Start Trigger implemented, attached below. Hope this helps!


Multi Record with Start Trig.png

Daniel S.
National Instruments
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Message 2 of 12

Hi Dansch,


It helps and works fine. Thanks you.Smiley Very Happy

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Message 3 of 12

Is there any way to set the polarity of the start trigger etc... in the same way as is possible with the Digital Edge trigger in your example?



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Message 4 of 12

Hello FJA,


Unfortunately, only the reference trigger slope may be changed at this time. The acquisition arm (start) trigger defaults to rising edge.



Daniel S.
National Instruments
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Message 5 of 12

Ok, thanks.

what about making the acquisition retriggerable. I want to do this on receipt of a new start trigger, any easy way to do this?

thanks in advance.

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Message 6 of 12

You can simply specify the source of the Advance Trigger to be the same as the Start Trigger source to get the functionality you are looking for. There are some good topics in the help file regarding multi-record acquisitions, as well as a couple of shipping examples, though I do not believe they show the advance trigger functionality. In general, they just utilize an immediate advance and then rely on the reference trigger to determine which samples to take. While it may seem daunting at first, another good resource to take a look at regarding the flow of the acquisition and the transitions of the device is the Acquisition Engine State Diagram. Here you can see exactly what each of the different triggers is doing and what events are taking place.


Best regards,

Daniel S.
National Instruments
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Message 7 of 12

Can someone support me with some idea?


Ive been trying to analyze phase difference between 2 encoder pulse (pulse  A and B). So far no function in labview support this kind of analysis ( please refer attachment ). I need to get "result wave" as in the attachment picture to calculate the value of phase difference between pulse A and Pulse B


Im using PCI 5102 hardware  and input came from encoder with pulse A and Pulse B

Download All
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Message 8 of 12



I tried to use this code with my PCI-5105 NI-scope card, but I wasn't able to get it to run using an analog trigger to start the recording.


What do I have to pay attention to make my input signals acceptable as start trigger source?


Thank you,


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Message 9 of 12


Can anyone help me, I'm using NI PCI 5922, I installed the labview (8.5.1) and I installed the NI-Scope driver and I tested it with the MAX and it passed the self test and I can see the test panel even I connected my digitizer to a waveform generator device and it works perfectly! But when I started to manage it pragmatically it labview, I didn't find my NI-Scope driver under the Instrument drivers in the Functions of the Block diagram!

I appreciate your help,



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Message 10 of 12