04-25-2019 03:36 PM - edited 04-25-2019 03:48 PM
I have an application that uses Ni-Scope drivers and a NI USB-5132 oscilloscope. I am currently adding a single sweep feature to the scope to we can capture inrush currents.
Now obviously I am wrong because it does not work this way but my thinking here is this:
No matter what I try I always get TWO SWEEPS!
I lose the inrush capture because when the scope stops it is displaying the second sweep.
I have attached a stripped down version of my program with all the non-scope related stuff taken out.
04-25-2019 03:54 PM
Sigh. Ever since oscilloscopes went digital, I've been lost (and I'm talking about a Tektronix 3034, a fairly old scope). When everything was analog (including the "moving beam"), I could believe what I was seeing and, even better, understand what I was doing ...
Is there a possibility that there's a "pre-trigger" sitting in there? What if you start an acquisition and give it no trigger? Do you see nothing, or do you get a sweep ("I know he wants to see something ...")?
Bob Schor
04-25-2019 04:02 PM
@Bob_Schor wrote:
Is there a possibility that there's a "pre-trigger" sitting in there? What if you start an acquisition and give it no trigger? Do you see nothing, or do you get a sweep ("I know he wants to see something ...")?
Bob Schor
I see nothing, it just sits there waiting for a trigger like I would expect.
04-25-2019 04:06 PM - edited 04-25-2019 04:08 PM
So thinking about the pre-trigger...
I kind of use 50% pre trigger by default here as I do in an actual DSO so the trigger point is centered on the screen.
I and beginning to wonder if it's not so much that I am getting two sweeps, but that one sweep after %50 pre trigger and not fit on the screen and I am just not seeing it all, just the end?
But then again that does not make sense, because why even have a pre-trigger if you can't display it?
04-25-2019 04:47 PM - edited 04-25-2019 04:48 PM
I have further removed extra parts so now anyone with NI-Scope and the appropriate hardware can run my code
04-25-2019 05:23 PM
Go to the View in the menu and and open "Event Inspector Window"
I have not looked in detail at your code, but you have multiple event structures and value signaling properties. I wonder if your Event is getting triggered twice, then two acquisitions.
The Event Inspector Window has a log of events, check if that is the case.
mcduff
04-25-2019 07:12 PM
Can someone inline a png or snippet?
My 8-Ball is telling me that you are making a simple mistake and probably should be using a start-fetch rather than a start-wait-read.
04-25-2019 07:18 PM
04-25-2019 07:31 PM
Dang, I still can't tell from my phone...McDuff, can you print the lower loop and inline the png?
04-25-2019 07:41 PM
Sorry, just left the office without LabVIEW.