topic Re: data generation from NI CARD in Signal Generators

data generation from NI CARD

bharath_reddy — Mon, 21 Apr 2008 12:59:33 GMT

   How do i generate a waveform from the data i have in 'MAT' file or 'text' file say, for many number of times continuously/repititively by using NI card BNC-2120???. For the real time implementation of one algorithm i need this.Thanks in advance for answering.

                                                                                                                                                         Bharath.

Re: data generation from NI CARD

JoeFriedchicken — Tue, 22 Apr 2008 17:48:27 GMT

Hi Bharath

This application is quite common and another customer brought it up in a different thread [1]. Your application is slightly different, though, because you want to repeat the output of the waveform. Instead of disabling regeneration like the other thread, I would leave it enabled.

If you would like further clarification, please reply with your questions and the hardware that you're using. So far, you mentioned a BNC-2120, but that is just a connector block. It should be connected to a DAQ card, and I would like to know what DAQ card you're using. Also, what kind of singals are you generating -- what shape, frequency content, duration do they have? What kind of timing requirements do you have -- why do you need real-time?

[1] problem with my output waveform from usb-6215
http://forums.ni.com/ni/board/message?board.id=250&view=by_date_ascending&message.id=38029#M38029

Re: data generation from NI CARD

bharath_reddy — Wed, 23 Apr 2008 04:32:17 GMT

Hi Joe,

             Thanks for your reply. Actually,i am not using any hardware here.My purpose is to generate the   continuous (signal) waveform on CRO with the text data i have.I am using labview for this kind of generation. I am taking analog outputs on BNC-2120 which is connected to the computer,and observing it on CRO and furthur usage for my algorithm.

                        I am using a simualtion data as a real time one by repititively generating.The signal is fault current waveform data of 16000 samples,frequency=50,sampling period=10 microseconds which is almost sinusoidal with high amplitudes in certain periods.Do you have any suggestions for this.

Thank you,
Bharath

Re: data generation from NI CARD

JoeFriedchicken — Wed, 23 Apr 2008 21:30:16 GMT

Hi Bharath,

I'm sorry, but I still don't understand your equipment setup. You have a BNC-2120 and an external oscilloscope, the CRO. You have a text file of data points which you want to use to generate the waveform.

I'm not familiar with your CRO, but I don't know how you're going to create this analog output with it. What device will make the waveform? How will you measure it -- with the CRO or with your BNC-2120? How is the BNC-2120 connected to your computer?

Re: data generation from NI CARD

bharath_reddy — Thu, 24 Apr 2008 09:01:30 GMT

Hi Joe,
I have text file or MAT file data with me.This data is used in one algorithm it is working.But the real time implmentation of the algorithm i want to generate the input continuously that means repitively.So how do i generate the signal or waveform,if i do that i will implment the algo.. on dsp processor.

So,if you have any ideas how do i generate the signal or waveform on CRO using Labview please share with me.
Bharath

Re: data generation from NI CARD

Dennis_Knutson — Thu, 24 Apr 2008 13:42:27 GMT

If by CRO you mean an oscilliscope, that is not capable of generating any type of waveform. It is a measurement device. You've been asked a couple of times what kind of hardware you have and you said you had no hardware. How do you expect to generate a waveform? A BNC-2120 is just a dumb terminal block and can't generate a signal either. Before you worry about reading an external file, you should think about the basics.

Re: data generation from NI CARD

bharath_reddy — Fri, 25 Apr 2008 03:22:03 GMT

I am sorry for not being quite clear in question.I want to generate the waveform by using some Labview simulation.And i want to check it on Oscilloscope.
Is there any simulation possible in labview for this aspect???

Re: data generation from NI CARD

Dennis_Knutson — Fri, 25 Apr 2008 14:07:09 GMT

How can you expect to get a software simulated signal to a scope without any hardware to physically generate a signal. Do you think the signal can magically jump from pc memory to the voltage input of the scope?