Scope acquisition returning zero signal level 80% of the time

[JesusF]

Hi. I am acquiring a 2 channel signal from an Agilent DSO7104A (1GHz) scope. Whether I use the single shot run or the continuous loop in the Labview front end, I only obtain a good signal once out of every 7-8 shots. The other signals are flat lined at zero. This is causing me to have to acquire thousands of shots so I can filter out the zero level signals and average the others. My company will not allow me to post any attachments so I cannot show you the code - but I have taken the BASIC labview example for agilent oscilloscope multichannel acquisition - there is nothing new or funny in there, in fact I copied and pasted it and just added a write to file and edge trigger. Can anyone help?

[BillMe]

I use a DSO and don't have that issue. Where did you find the LabVIEW example and where did you get your drivers?

If not the code, can you post a screenshot?

[JesusF]

Unfortunately I cannot upload ANY document from my computer here, Aramco is recovering from an internet virus attack and has restricted ALL uploads and downloads of any nature. If you have an email address I can email you a pdf of the screen shot. My driver is ag6000. I got the example after I installed the driver from LabView from Getting Started Screen / Find Instrument drivers / Connected Instruments / then double clicking on ag6000 and it has several examples including acquiring multi channel waveforms. I literally copied and pasted the code then just added an edge trigger and write to file. I have tried adjusting trigger times - doesnt seem to make a difference. Can you let me email you?

[BillMe]

Sorry, I'd rather not do that.

Some questions:

How often are you triggering the scope and writing to file? If a slow enough rate, can you observe the scope front panel, do all the traces look as expected?

[Alex+ra]

Hi JesusF,

Try running the example exactly as-is. Don't copy the code, don't modify it, just run it. Do you see the same behavior? 

Regards,

Alexandra

[Aojha]

if the example is assosiated with any property nodes, then it may modify while doing copy-paste. But in that case result will not come any time.

How you are connected to scope LAN or GPIB?

When you are getting exact results (in the first attemp or randomly)?

Sometimes I get problem with Lecroy Scope then I Reset LAN cofiguration and things start to work for me.