NI SCOPE digital trigger slope

[bmetz]

I have a problem trying to use digital triggering with a USB-5133 digitizer.  I'm using NI-scope (3.5) and C.  My software doesn't appear to be able to change the trigger slope (using niScope_ConfigureTriggerDigital()).  There is no problem if I use analog triggering.

The problem is not isolated to my code.  I see the same behaviour with the NI-SCOPE Soft Front Panel (version 2.9).  In that application, if I connect the triggering input to PFI 1 and select digital trigger, then the slope selection has no effect.   However, by briefly selecting "edge" triggering, changing the slope in that mode, and returning to digital trigger, I find that the triggering is now working according to the slope selected in the edge triggering mode.

Although niScope_ConfigureTriggerEdge() seems to work o.k. (using an analog input) and niScope_ConfigureTriggerDigital() doesn't, the following sequence doesn't provide a work-around:

 niScope_ConfigureTriggerEdge(...);

 niScope_ConfigureTriggerDigital(...);

The PFI 1 input looks o.k., although initially I had been feeding it straight from a 5 V CMOS gate.  Adding a divider to the input to bring the voltages to swinging between 0 and 2.8 V had no effect upon the behaviour.

[Brandon_B]

Hello bmetz,

Thank you for using NI forums.  This sounds like it could be a bug but I won't know until I try it on my end.  How wide is the trigger that you are using and what is the frequency of the signal you are measuring?  If you could include some screenshots that would be a great help as well.  Also, towards the end of your post you said the following sequence "doesn't" provide a work-around.  Did you mean to say the following sequence "does" provide a workaround.  I ask this because at the beginning of your post you mentioned that you were able to change the trigger to edge triggering, change the slope, and then go back to digital and it worked.  Please let me know if I misunderstood what you were saying.

Regards,

[Jennifer O · Accepted solution]

Hello Bmetz,

This is a known issue which has been fixed in NI-SCOPE version 3.5.1. You can download and install the update through the Drivers and Updates page here:http://joule.ni.com/nidu/cds/fn/p/sn/n23:3465.40/lang/en

You will find a list of bug fixes in the readme, including the following:

123308: Fixed an issue with inconsistent triggering when changing the trigger edge on the NI USB-5132/5133. 

Hope this helps,

Jennifer O.

Product Support Engineer: High Speed Digitizers

[bmetz]

Thankyou Jennifer,

It turns out that I have actually wasted everyones' time.  I had downloaded NI-SCOPE version 3.5.1 in early June.  When I discovered the triggering problem I assumed that I had installed the downloaded version (it looks like I must have distracted by something urgent at the time...).  The check I did in Windows showed version 3.5 but I (wrongly) assumed that the ".1" was simply left off (there is the strange issue of the downloaded NI-SCOPE containing an NISCOPE351 and an NISCOPE3512 directory).

Anyway, I have now run the setup.exe in NISCOPE315/ to install version 3.5.1 and now the NI-SCOPE Soft Front Panel correctly sets the digital triggering slope. The "C" call appears to work correctly too.