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NI-FGEN Ready For Start Event

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Hi all,

 

I've got an FGEN card (PXI-5441) in my PXI chassis, with a PXIe-8821 embedded controller running a custom firmware application. I've been using the FGEN in script mode to generate waveforms submitted from the FW indefinitely. I would like to implement a way for the FW to know when the FGEN has started ouputting the waveform it was told to. In other words, the FW will send a software trigger to advance to the next part of the script, and then monitor [insert solution here] to confirm that the next part of the script is live. 

 

The Wait Until Done VIs will NOT work for this, since this is a not single trigger mode application, it's continuously generating. I tried to learn more about the Ready For Start Event, since you can monitor the live status using property nodes. But there is no documentation on how to use this event! Do you write it into the script?

 

Has anyone had experience with this event type?

 

 

Thank you,

Michael

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Hi Michael,

 

It looks like this has been open for awhile - have you been able to get this functionality working? 

 

I can't find a specific example of what you're looking for but maybe some documentation will point you in the right place.

 

1. Common Scripting Use Cases

http://zone.ni.com/reference/en-XX/help/371025V-01/rfsg/scripting_use_cases/

 

The condition branching section is one that should help you with triggering the FGEN software multiple times. 

 

2. Here's documentation of FGEN events. Based off what you described, I think you're looking for the Started event as opposed to the Ready for Start event.

http://zone.ni.com/reference/en-XX/help/370524V-01/siggenhelp/fevents_fgen/

 

3. As a general starting place, the Fgen Arb Script.vi included with the FGEN driver can be helpful.

 

Best,

Ben

Technical Support Engineer

National Instruments

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Accepted by topic author michael.lambert

Hi Benjamin,

 

Thanks for the reply and those useful links. I had seen the scripting use case page before, but completely missed the conditional branching section! 

 

I ended up going a different direction since the system is constantly generating, so there are no start triggers (rendering the start and ready for start events pretty much useless). Instead, I added a line before each "repeat until" section of the script. This line just generates the waveform once with a marker at position 0 (output to PFI1 for data collection) - example in bold below:

 

generate waveformA marker2(0)

repeat until ScriptTrigger0

   generate waveformA

...

 

Since there is a property node for marker latched status, I can monitor this marker's status to tell if that line has executed. If it has, that means the new waveform should be generating. Once it goes true, I notify the user that it successfully updated and then I set the marker's latch status back to false.

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