Measure a Linear Scale Unit, with sine wave signal

I have a Linear Scale Unit, with three outputs, Phase A, Phase B and Scale ABS point. The outputs signals are in sine wave, with Phase difference of 90º. I have a NI PCI-6034E, and I don't know how to read that signals and convert them in mm and also put them in LabView program. I only find Quadrature Encoders. I don't know if it is better read the signal by the counter or analog input line.
Thanks and Best Regards

Hi Luis,
If your inputs are sine waves, you're probably best off using analog input, though if the voltages are correct, you might be able to use counters.
The conversion from the voltage outputs to mm distance is dependent on the sensor, so you will have to look in its documentation or search the web to find the parameters for your device. Once you find these values, you should be able to convert with a pretty simple LabVIEW application based on the input signals, either using their exact values or counting cycles, whichever is appropriate for your sensor.
If you need more help with the conversion, please post more detailed information on the encoding of your sensor.
Thank you,
Kyle Bryson
National Instruments

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Measuring lag between input and output sine waves...

Hi,
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Since I work with lock-in amplifiers I came up with this. I guess it will work in your case. This method has some limitations. It will work up to 180 degree. It also measure absolute phase lag. You can not say if the signal is leading or lagging. But in your case it will always be lagging. I posted a VI showing the method in another discussion. Here is the link. http://forums.ni.com/ni/attachments/ni/170/409516/1/demo_v2.vi. Since your DAQ unit do not have simultaneous sampling you will get a small phase error due to inter-channel delay. This is also true if you use the FFT method. What is your signal frequency and which samplerate do you use?
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Hey Eldokch,
See step 4 in the following white paper:
http://www.ni.com/white-paper/13880/en/#toc4
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I have a 50Hz sine wave and a pulse signal on a same graph. The phase difference between two is between 0-90 degrees.
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Cheers
Awais
Message Edited by awais.h on 03-30-2010 11:20 PM
Message Edited by awais.h on 03-30-2010 11:21 PM
Solved!
Go to Solution.

Hi
Thanks for the code but I'm afraid it won't work. Like you said the probability of choosing a value that is on both graphs may not happen. This is something that I would like the code to do automatically.
But I did use the previous code posted and made some modifications to it and it seems to work perfectly. Now the next thing is to be able to get just that one value that tells you the first time difference.
Here is what I get using that code.
As you can see from the t Values. I only need the one that is highlighted. If there is a way to filter out the rest it would be great.
I was thinking of a while loop and as soon as the value is higher than 3E-5 it would store the number and stop the loop, but I'm not too familiar with arrays in labview.
Here is the the code modified.
As you can see, it wasn't that big of a modification and it still is your code.
I will keep trying.
Thanks for the help
Attachments:
FinalShockSpeed.vi ‏55 KB

Will PFC power supplies work with SIMULATED sine wave inputs

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Just looking for advise on the best way to measure superimposed frequencies on my raw data. The raw data (voltage versus time) is ultimately a noisy sine wave with a frequency of 1Hz. I need to determine where the noise is coming from, i.e. is it vibrational, electrical or surrounding noise, hence requiring the frequency of the noise if possible.
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John,
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Hi,
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Message Edited by Jaime F on 02-06-2008 11:42 AM
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How can i do a sine wave with High Throughput Sine for fpga?

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I need to do a sine wave with high throughput block. In my exercise i have 2 inputs (amplitude and frecuency) and i have to look the output (sinewave)
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Hi pablosan,
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Hi Folks.
I am trying to measure the signal deformation coming from a scope. Its a typical sine wave that distorts as the input increases (shown in the attachments). I was initially just going to subtract a known signal from the recieved signal to give the difference. The point by point error is to big for this. I am also trying to determine the slope over time and the rapid change of slope would indicate the point. However point by point calculation of the slope gives too much error to. Is it possible to generate accurate slopes or is there a function that determines if a signal is non-sinusoidal??
Thanks,
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Solved!
Go to Solution.
Attachments:
Sine1.jpg ‏26 KB
Sine2.jpg ‏26 KB
Sine3.jpg ‏26 KB

For a quick visual check you can use the tone detection vi and export the residual signal, maybe the rms value of the residual is a nice value (THDN)
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Your traces look like a 1g steel ball accelerometer calibration to me.
Greetings from Germany
Henrik
LV since v3.1
“ground” is a convenient fantasy
'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'

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Hello, Rilee,
Thank you very you very much. But I am still confused. The website I can not open. As you said, I shall create a data array to contain three phase data, for example, sinedata[750], sinedata[0:249] contains first AO, and sinedata[250:499] the second, and the rest is the third. then
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Measure a Linear Scale Unit, with sine wave signal

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