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Non-invasive AC current sensor

What do you have the current sensor clamped onto?

Have you contacted the vendor? You don't have a LabVIEW problem.
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Message 11 of 21
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@gazza48h wrote:

i tried that circuit and sevsral simular circuits but cannot get a reading off my multi meter. I cannot understand it?? Any ideas?


Dennis is right you really do not have a LabView problem. But I will give you some hints. Your current transformer is rated at 1V=30Amps. That means about 0.033V/Amp. So unless you have this placed over a rather large current source it's going to be hard to read with a meter. Also remember that the CT will output an AC voltage.

 

The Arduino circut sets a 2.5VDC offset, so 0 amps = 2.5VDC and 30 Amps = 2.5VDC with 1VAC riding on top of it.

The software then removes the offset and does an RMS calculation on the ramaing AC component.

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Unfortunately, most readers of this Forum, including some real Experts, have not mastered the skill of being able to read the code that Posters fail to post. If we cannot see "what you did wrong", we are unable to tell you how to fix it. (Bob Schor 28 August 2018)
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Message 12 of 21
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Another hint (that I hope is not necessary Smiley Wink).  You'll need a single wire with current flowing in one direction.  You cannot just clamp it onto the power cord of a lamp for instance. You would need to strip one conductor out and clamp around that.  

LabVIEW 8.5.1 - 2018 Pro Dev
Message 13 of 21
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Thanks for the info. I figured out that i am only reading a current of 1 - 1.5 A which outputs a very low AC voltage of 34mV which my multimeter was unable to read. How will i interface this AC signal with my arduino and labview. Will i have to amplify the signal so the arduino can read it between 0 - 5v but that will still be AC. How do i create a DC signal so i can read it with  my arduino. I dont have great knowledge when it comes to voltage measurments so please bare with me. Any detailed help much appreciated Smiley Happy

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Message 14 of 21
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@gazza48h wrote:

Thanks for the info. I figured out that i am only reading a current of 1 - 1.5 A which outputs a very low AC voltage of 34mV which my multimeter was unable to read. How will i interface this AC signal with my arduino and labview. Will i have to amplify the signal so the arduino can read it between 0 - 5v but that will still be AC. How do i create a DC signal so i can read it with  my arduino. I dont have great knowledge when it comes to voltage measurments so please bare with me. Any detailed help much appreciated Smiley Happy



Did you read my previous posts about using a DC offset or look at the example DC offest circuit and Ardunio code I linked to that uses this exact same sensor?Smiley Frustrated

 

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Unfortunately, most readers of this Forum, including some real Experts, have not mastered the skill of being able to read the code that Posters fail to post. If we cannot see "what you did wrong", we are unable to tell you how to fix it. (Bob Schor 28 August 2018)
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Message 15 of 21
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thanks for your help, i built a non inverting op amp to generate my signal for my arduino to read. I came across a problem. All my analog input pins seem to be floating high to low when there no connection to the pin. Therefore when i connect my op amp to my arduino pin the readings are counteracting each other. Therefore i cannot determine my reading from my op amp.Hope i make some sense as its difficult to explain. Really need some help as i cannot get current reading from my tansducer onto my arduino.

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Message 16 of 21
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What do you mean by "counteracting each other"?

 

Do you mean something like ghosting?  http://digital.ni.com/public.nsf/allkb/C6C7DE575301A379862572DD00480A01

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Message 17 of 21
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@gazza48h wrote:

thanks for your help, I built a non inverting op amp to generate my signal for my arduino to read. I came across a problem. All my analog input pins seem to be floating high to low when there no connection to the pin. Therefore when i connect my op amp to my arduino pin the readings are counteracting each other. Therefore i cannot determine my reading from my op amp.Hope i make some sense as its difficult to explain. Really need some help as i cannot get current reading from my tansducer onto my arduino.


 I have tried to help as much as I could as I have played around with an Arduino and have experience using current sensors. But I hate to say it this is defiantly not a LabView problem. I believe you need to read up on the Arduino and ask your question on an Arduous hardware based board.

 

Analog in pin description

http://arduino.cc/en/Tutorial/AnalogInputPins

 

Tutorial on reading analog input with native Arduino code (Wire)

http://arduino.cc/en/Tutorial/AnalogInput

 

Tutorial on reading analog input with LabView Arduino library

https://decibel.ni.com/content/docs/DOC-16067

 

LabView community dedicated to LabView Arduino library

https://decibel.ni.com/content/groups/labview-interface-for-arduino

 

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Unfortunately, most readers of this Forum, including some real Experts, have not mastered the skill of being able to read the code that Posters fail to post. If we cannot see "what you did wrong", we are unable to tell you how to fix it. (Bob Schor 28 August 2018)
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Message 18 of 21
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Basically i have 2.40v AC comming into my arduino but i cannot pick it up. Why is this?

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Message 19 of 21
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@gazza48h wrote:

Basically i have 2.40v AC comming into my arduino but i cannot pick it up. Why is this?


The analog input pin voltage is limited to 0-5VDC. Anything outside that range will damage your microcontroller.

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Unfortunately, most readers of this Forum, including some real Experts, have not mastered the skill of being able to read the code that Posters fail to post. If we cannot see "what you did wrong", we are unable to tell you how to fix it. (Bob Schor 28 August 2018)
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Message 20 of 21
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