Ni Scope

[R_J]

Hi

We are using an oscilloscope for measuring Duty cycle , hold time & frequency of a signal.Can we replace Oscilliscope from the NI-scope . We have to show frequency , duty cycle , hold time , all the waveforms etc

what is NI Scope & when we can use it

Please reply

R j

[Dennis_Knutson]

NI Scope is the software used for the NI scope boards like the ones at http://www.ni.com/digitizers/. Big advantages of a pc based scope board is the much faster transfer rate as compared to GPIB and lower cost.

[R_J]

Hi

Please explain more . As i had already explain the requirements . Could we use NI Scope in place of oscillator.

regards

RJ

[Dennis_Knutson]

You'll have to go to the web page I mentioned and check the specs for # of channels, sample rate , etc. The measurements you want to are all possible but, at this point anyway, only you know the specs on your current scope and waht is required.

[DFGray]

The NI-Scope Soft Front Panel is an application which ships with all NI high speed digitizers.  It can show as many waveforms as there are channels in the scope card, plus references, if you read them in.  It includes common scalar measurements (e.g. frequency, duty cycle).  The only problem you may have is hold time.  I don't know how you are currently measuring this, so cannot definitely tell you it will work.  If you have a driver CD, you can install NI-SCOPE and check it out in simulation mode.  Alternately, if you have NI-DAQ and/or NI-DAQmx installed, you can download the NI-SCOPE driver from ni.com and do the same.  Let us know if you have any further questions.

[50ohmTerminator]

Hey RJ,

I just wanted to add a few things to the posts above. The PXI based digitizers can perform most of the measurements that regular oscilloscopes can. NI-Scope is the driver that these digitizers use. You have many options and you can pick one that will be best suited for your application. A couple of things that might help you decide which digitizer to pick is the frequency range, voltage range and the precision you are looking for.

Our newest digitizer,the PXI 5152 can sample upto 2 GS/s real time (single channel) and it has 8 bit of accuracy.

The PXI 5124 can sample upto 200 MS/s and has 12 bits of accuracy.

You can find the list of digitizers along with their specifications here.

These digitizers can definitely measure frequency and duty cycle. I am not entirely sure what you mean by hold time. If you can measure it using an oscilloscope, chances are you can use one of the digitizers. If you can describe what you are measuring for hold time we can figure out how to measure it using the digitizers.

I don't know if you've used LabVIEW before but it works great with these digitizers. You can acquire the data, do analysis and make a sophisticated user interface using this one program. Programming in LabVIEW is extremely simple as it is graphical. You can find out about LabVIEW here.

Let me know if you have any more questions.

Regards
Malay Duggar
Applications Engineer
National Instruments

[toh]

Hello Duggar,

I have a PXI 5102 digitizer and I have try using Labview with NI scope's driver to acquire the signals. So far, I have managed to acquire signals from both channels and display them simultaneously on the graph. However, how do I plot it against real time like a strip chart? I am trying to measure the timing different between the two channels when they are triggered at different instant.  I am looking at ms measurement. I have tried using the strip chart display but there are no features for measuring timing on the strip chart. Probably, I am not so familiar. I hope you could advise me. Thanks a lot.

Phooi

[parthabe]

I think the PXI 5102 is already obsolete, because we were using PXI 5112 a year ago, which is now turning out to be obsolete; NI is recommending PXI 5114 or even more.

Better you update NOT only S/W, also H/W.

[toh]

You're Right.

But now my main concern is to solve the issue of plotting the signal against real time. I believe this old H/W still can does the job. Would you kindly share your knowledge with me if you know?

[Yardov]

Hi Phooi,

I am not sure what do you mean by:

"I am trying to measure the timing different between the two channels when they are triggered at different instant"

The scope is sampling at the same time and therefore there is no time difference between them. The trigger is only one and you have time from when it happen to the first sample (of both channels).
Finally, to plot it as strip chart, you can just use a strip chart and it will use the embedded buffer to keep track of the previous samples. You can configure the length of this history by right clicking the indicator.
I hope this clears up the question,