graph scales & connection

[Serina]

Hi,

    I have some difficulty in the circuit connection and setting on scales for my output graph. I have tried different scales for X & Y,position,range(volts) and range(time) but i still cant get the waveform i want. The 2nd trial i manage to get a sine wave but after i edit the scales and circuit connection i cant get any waveform further. I am trying to connect the two 'software and hardware' waveform output together to a single stop button because i use two stop button, will lag and hang for few seconds. But i don't know need to use any specific VIs because i am not familiar with the VI. So anyone who can help please help me..What are the scales i should use for "X & Y,position,range(volts) and range(time)" (for the waveform connected to the hardware at the bottom) to have a waveform same as (upconverted waveform)and how to connect the circuit to use only one STOP button. (HP54600B oscilloscope, Agilent E4438C signal generator). Lastly i wish to know why is my function reading different from prev?

[MehakD]

As far as the stop button is concerned, I would recommend you to use a local variable to prevent the use of two start buttons. You can achieve that by right clicking on one of the controls in the block diagram and selecting create local variable.

As for the signals are concerned, could you provide me more specific information on the kind of signal you want to obtain, the scaling that you want to use(depending on the conversion that you want to perform), and what is the unexpected signal that you are obtaining. Also, could you provide a brief description of the circuit connections that you are using currently. Also, more information on the instrument drivers would be helpful in determining all the details.

[Serina]

Hi Mehak D,

                   Thanks for replying i almost give up hope that people will reply to my question cause it's complicated.

Firstly, my task is to obtain 2 matched waveform, in a simpler way of description, the program must show 2 similar waveform when i run the program. When you see the attachment i had uploaded, u can run it and change the setting for the 'M-ASK' to '2' you can see a waveform with a straight line in between long squarewave. That my project teacher mention it means 2 bits (i think so..or 1bit?) so when is '1' the square wave appeared and when is '0' it is a straight line, and because it's M-ASK=2, the waveform is simple and extreme jus 'high' 'low' 'high' 'low'. My objective is to obtain information from the hardware into the computer LabView exercise which match with the waveform on top. I just learn local variable function i will try it. Because i don't know what scales should be use for the 'signal generator information' i just simply see the result when it run and i assume it is auto scale. I just try both subvi scope and main ASK modulation program show a sine wave. I try to adjust 'time/div' knob counter clockwise i manage to see a square wave not very similar to the result i want and when i press stop it always stop and show half big square wave. When i run the main ASK modulation, although i get a sine waveform the oscilloscope will kept blinking and a sound 'click' simultaneously. When i tried to adjust the same knob, eventually there will be no result and 'stuck' when i try to press stop or other function. Therefore i have no choice but switch off and on the scope again. I really don't know how to set and adjust for the scales on the graph for 'signal generator information' and ranges beside the graph? I think the ranges,scales adjstment is needed cause i take reference from a previous exercise done by last batch of student, which i hope i am right. I don't know how to explain to you my circuit connection but if you can't see the Vi for any reason i have send a copy in picture file. Lastly, my hardware devices are HP54600B (oscilloscope), Agilent E4438C (250KHz-6.0GHz ESG VECTOR SIGNAL GENERATOR) The USB CABLE I used is NATIONAL INSTRUMENTS GPIB0 [GPIB-USB-HS].

Message Edited by Serina on 04-07-2008 05:54 PM

[Sputnikrent]

Hi Serina,

I cannot understand what are the things you want to achieve and what problems you are facing. Would it be possible to rephrase the information you have above into very clear and short statements that will explain what you want to be doing and what issues you are running into? Are you having trouble communicating with the scope? Or are you looking to adjust the graph size?

Unfortunately the application you have seems very specific and I am unable to run your code because I do not have the necessary hardware (HP scope, Agilent VSA) or the instrument drivers. I would like to try and help as much as I can though. Please specify very clearly what you want to achieve. Thanks!

[Serina]

Hi,

    because detailed information was asked but i not capable in writing descriptive short and simple answer so i write a long passage.. In short i need to show and obtain a square wave same as the graph above, 'ASK'. something like that : |||--|||--|||--|||  '1 0 1 0 1 0 1' (when M-ASK is change to '2'). This is the aim of my exercise. Actually i manage to 'grab' the waveform from the scope into the internal exercise but i just cannot adjust on the scope and get the same waveform as ASK graph on my signal generator information (which is the graph just below ASK graph), instead of square wave i obtain a sine wave. Sometime, when i adjust to certain measurement the graph cannot be obtain and have error. That's why i am also bewildered, why is it sometime success and sometime not. So i could not tell you i am actually facing 'cannot obtain waveform' or 'adjustment error' becaue i think is quite abit of both. I am facing a major problem here and a minor problem is i do not know what value to set for the ranges all this, just beside the signal generator information graph and scales x & y of the graph too. However i believe the 2 problems are closely connected if 1 problems is solve i am sure another will be resolved too. If you still have any doubts or any part of my clarification is unclear please feel free to ask me again.

[Sputnikrent]

HI Serina,

I'm still having a bit of trouble following your explanation, but let's try and work this through. You said that you were getting a sine wave when you should be expecting a square wave. I think what you mean to say is that you are outputting a sine wave from the signal generator, when you are trying to output a square wave like in the ASK graph. Is this correct?

I'm trying hard to understand here. Where is the ASK graph originating from? Isn't it coming from the scope? And is the scope getting the signal from the signal generator? It looks like you are taking a waveform from the scope, doing some signal processing to it, and it results in the ASK graph. So how is it you want the signal generator graph to look the same as your ASK graph?

When you say you try to adjust "certain measurement" to graph, what does that mean? What are you adjusting, and what is the error you get?

How would setting the value for ranges change anything? Why do you want to set the value for range?

[Serina]

Hi Rasheel,

                  In answering the 1st question you ask, is correct.

                  2nd question, the ASK is internal generate (by the Labview i think), this is what my supervisor always tell me; that these waveform were internal generate. Just by using the correct and suitable VIs i can run the ASK modulation, actually this ASK modulation is the same as a example in NI tutorial url.

http://zone.ni.com/devzone/cda/tut/p/id/6037

Although i redo it as a practice but it is the same.Did u see my attachment?? If you see those files u should be able to understand more clearly.

Right,i am trying to take/grab the result of the waveform or signal into the ASK modulation exercise showing the same waveform as the ASK modulating signal. The scope is taking result from the signal generator and transfer signal into the LabVIEW, because scope must be the middleman we cannot directly 'communicate' with the signal generator; it will be unsuccessful.

The certain measurement i mean when i 'anyhow' adjust the setting and knob on the oscilloscope trying to get the result. Because the result is in the scope i have to adjust by the scope in order to show the desired waveform into the LabVIEW, because inside the LabVIEW, it just serve as a purpose of showing the result. However,the scales on the signal generator information 'inside' the LabVIEW must adjust too ifnot the scales will be out of range, because it will have scales too so we cant say adjust the hardware scope only.As i try the previous project done by a student from the last batch of my project group,she adjust the ranges all this of the signal generator information (which is the hardware installed graph name below the ASK modulation) almost similar to the ranges and scales that is internal generate. That's why i think the scales in the scope and ranges & scales in the hardware installed graph is the key to display the same result.

AIM: Signal Generator Information display a same square waveform when i set the frequency, amplitude or any other necessary..same as the ASK graph.

[Dennis_Knutson]

I'm having a hard time understanding exactly what you are attempting and what your problem is. Is the signal generator and the scope separate from the ASK LabVIEW code? If it is, then might have a problem with the setup of the signal generator/and or the scope. If you can't manually setup the scope to display the waveform your expect, then you have incorrectly setup the source or the scope. Don't mess around with any LabVIEW code until you can see the correct waveform on the scope itself. If the scope itself is displaying the correct waveform, then that would be a different issue.

[Serina]

Hi,

    actually like what i have mention, only when you see the files then you will have a clearer image of what i am talking about cause sometime wordings can't explain everything and my vocabulary is lousy too. So may have confused you. However, if you have seen the files yet you still don't understand then i am sorry and helpless now. Cause i have rephrase and explain a few times i don't know what words i can still use to explain.

Yes, the graph is different connection and not connected with the ASK graph. I think i never mention they are link.?? Sorry, if i never state clear enough. Maybe my message title confused people, 'connection' actually refer to the stop button problem and 'graph scales' error in obtaining graph. I am purely asking how to adjust on the oscilloscope setting, scales & the ranges, scales IN LabVIEW real time signal graph 'Signal Generator Information' [SGI] to obtain a square wave same as the ASK graph (because a correct scales is needed inside LabVIEW [SGI] WHEN i want to grab the result from the scope, 2nd procedure). I just want to display a Square Wave Similar with ASK M-ASK '2' Square wave. ASK is running on its own, the connection is okay.

In short, i cannot display a square wave similar with ASK M-ASK '2' in either oscilloscope or LabVIEW.