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Voltmeter for AC 415V

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gauravkothari23

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Hi all...
i need to make a voltmeter using 89S52, 20x4 LCD and ADC0831 to measure voltage upto 415V. can any body please help me or guide me how can i do this.
i have interfaced 20x4 lcd with 89s52 and measururing a DC volt upto 5V is also not an issue. but how can i do for 415V.
 

Hi,

A frequently asked question, therefore you will find a lot of useful discussions here. Just do a forum search.

The solution depends on:
* isolated or not
* true RMS, or - what I call - "fake RMS", or any other method.
* is it clean sine wave?
* what resolution?
* does it contain DC?
* what's more easy for you: hardware or software?

Klaus
 
Hi,

A frequently asked question, therefore you will find a lot of useful discussions here. Just do a forum search.

The solution depends on:
* isolated or not
* true RMS, or - what I call - "fake RMS", or any other method.
* is it clean sine wave?
* what resolution?
* does it contain DC?
* what's more easy for you: hardware or software?

Klaus
Thanks KlausST
no i am not using isolated circuit.
not the hardware as well as the software part is easy for me... i have to go through some of the documentation as well as need some expert guide.
i have tried preparing a small hardware but not yet tested. attaching the schematic , kindly please let me know if the hardware will work or not. as in the schematic, Neutral line of 415V AC is connected to common GND of my complete circuit which works on 5V DC. wont this create any issue. or it can be dangerous.
Sorry for not showing crystal and reset circuit.
 

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  • ADC0832.png
    ADC0832.png
    48.6 KB · Views: 40

Hi,

You just answered a single question:
* "not isolated".
Then you asked: "can it be dangerous"
--> yes, seriously. Don´t hurt yourself or others. It seems you are not experienced enough to manage this project.
Are you familiar with the safety regulations of your country.

Technically I doubt this will work according your expectations. But this is just an assumption, because you don´t tell us your expectations.

Klaus
 

Hi,

You just answered a single question:
* "not isolated".
Then you asked: "can it be dangerous"
--> yes, seriously. Don´t hurt yourself or others. It seems you are not experienced enough to manage this project.
Are you familiar with the safety regulations of your country.

Technically I doubt this will work according your expectations. But this is just an assumption, because you don´t tell us your expectations.

Klaus

yes you are right... i am not experience enough to manage this of projects. This is the first time i am working with such high voltage.
so i request you to please give me some ideas for designing any reliable circuit because software part wont be an issue for me.
so please let me know how can i do this. do i need to add a transformer and convert it to 5V DC so that i get a isolated output. using a transformer can be a bit issue for me because of limitation of size of my board. so i thought of using such circuit.
 

Hi,

A transformer gives additionaly safety.
But as long as you don´t answer my questions, like: "* does it contain DC?".. I can not recommend a transformer, since a transformer will be killed by DC.

Maybe other members can help you without additional informations. But I don´t spend my time to ask a third time....

Klaus
 

Hi,

A transformer gives additionaly safety.
But as long as you don´t answer my questions, like: "* does it contain DC?".. I can not recommend a transformer, since a transformer will be killed by DC.

Maybe other members can help you without additional informations. But I don´t spend my time to ask a third time....

Klaus

i am sorry for that...
no it does not contain any DC.... the voltage to be measured is completely 415V AC

- - - Updated - - -

Do i need to convert this 415V AC to DC
 

Can i use LM258 operational amplifier. I got one of the circuit from google.
 

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  • _20170612_190532.JPG
    _20170612_190532.JPG
    160.4 KB · Views: 36

Short answer: if this is your first time doing this type of project, the answer is no.

415 VAC means that you are measuring line-to-line in a 3 phase system.

These lines will be 415/sqrt(3) = 240 volt from ground. Presumably, they will also high current capabilities. A dangerous situation.

Use a step down transformer as suggested previously.
 

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