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I am using the VISA pallete to acquire array of amplitude values (100 values) from CCS C compiler. Using this array, how would I generate a sine wave? I have attached what I have so far. Help would be much appreciated!

01-10-2017 08:14 AM

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01-11-2017 05:37 AM

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You need to explain what you are trying to do. Right now you are calculating the sine of your acquired data, is it what you want?

You will only get a 'sine wave' out of this if your acquired data is a ramp signal of some kind. Also your converted data is integer, so probably not a good resolution to use as input to a sine function. What is you data range and what are these 'amplitudes' representing? What is your end goal?

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So, I have connected a microcontroller (pic18f6722) to the function generator. I have set the ampltude to 4.5V and the freq to 60 Hz on the function generator. If i were to connect the function generator to an oscilloscope I see a unipolar sine wave with an offset of 2.25V. I basically want to recreate that sine wave on labview. I have written code to collect the values of the sine wave and now I have used the VISA palletes to get the array of values in labview and make a graph out of it.

01-11-2017 08:28 AM

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01-11-2017 08:33 AM

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Hi beginner,

I basically want to recreate that sine wave on labview.

I have written code to collect the values of the sine wave and now I have used the VISA palletes to get the array of values in labview and make a graph out of it.

And what's your problem when you already have written code?

Best regards,

GerdW

using LV2011SP1 + LV2017 (+LV2020 sometimes) on Win10+cRIO

GerdW

using LV2011SP1 + LV2017 (+LV2020 sometimes) on Win10+cRIO

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Thanks for the reply! And the code is over at CCS C and since I am a begineer at serial communication and labview I had some trouble generating a sine wave. I came close but the wave looked like a step function.

01-11-2017 08:35 AM

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and it still doesn't explain why you are calculating the sine of your data (sine of sine if you original data already represents a sine wave). Could you at least post a data file with 'Voltages' values so we understand what you are acquiring?

01-11-2017 08:52 AM

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I have attached an excel sheet with the voltage values acquired. For the time, it starts at 333us because that was the delay i used over at CCS C compiler. The graph shown in the excel sheet should be the graph i should be getting in labview

01-11-2017 08:59 AM

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01-11-2017 09:23 AM

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ok, get it. Your data consists of your sine tone data but I guess you do not read the time array.

If you extracted the two columns in your spreadsheet and created X (time) Y(Voltages) data arrays then you could graph it on a LabVIEW XY graph and get the same look as in your spreadsheet.

In your actual VI I would suggest you to try the following (to start with)

1 - Remove the sine primitive

2 - Replace the **Decimal String to Number** primitive in your FOR look with a **Fract/Exp String to Number**

3 - Graph the array out of your FOR loop directly to a waveform graph

If it looks like a sine tone, then you can move on and work on the time information (dt)

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I only extracted the voltages from labview. I just used the time on excel to see how the graph would look like. How would I create a time array?

01-11-2017 09:26 AM

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01-11-2017 09:34 AM

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From your XLS it looks like you are sampling at 3 kS/s (dt = 0.33 ms).

Use the **Build Waveform** (Waveform palette) and input 1/3000 to the dt terminal and your data array to the Y terminal and graph it (likewise on a Waveform Graph).

If you can't get it to work, try to post you **Voltage** string array with saved values so we can check your string formatting.