Codes for ADC on PIC16F877

[Asabzi2000]

Hi
Am designing an Automatic Transfer Switch with 3 analog voltage sensors. I need some codes to be able to detect the analog values at the ADC of the PIC. Any help please. Attached is my circuit. Am using mikroC

 

[jayanth.devarayanadurga]

Your circuit shows that RA0, RA1, and RA2 is given pulse input and not ADC input. You have to give analog voltage to ADC pins and then write ADC code to get the analog value.

 

[kabeer02]

You have to specified the value first, since you have 3 phase signal at what condition did you want control the change over?

 

[jayanth.devarayanadurga]

How can opto-isolater work as analog voltage sensors?

 

[Asabzi2000]

Hi Jayant, This is how I want my system to work. The load is supplied by utility at 240V 50Hz. When utility goes off I want to automatically detect it using the MCU, then start the gen set automatically and then hook the load onto gen set. Pls any suggestions!

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Hi Kabeer am sensing the presence or absence of 240V 50Hz to load. When it goes off, I want the controller to detect it and issue command for a genset to start. When the genset develops rated V. Then the controller commutes the load to genset through a stepper motor. Pls suggest how I can do it well. Any schematics will be appreciated. Am using mikroC compiler and proteus design suit

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Jayanth, pls what do you suggest?

 

[jayanth.devarayanadurga]

Then you don't need ADC for that. Just isolate the 230 V using opto-isolator use a capacitor at the output of opto-isolator so that there is no ripple of your 50 Hz. Make sure that it gives voltage = VIH of MCU digital input pin. If voltage is present at the digital input pin of MCU then genset driving relay is OFF. If there is no voltage then MCU turns ON the relay which drives the Genset.

 

[kabeer02]

okay now since you have 3 phase what will happen if only 1 or 2 phase went off?

 

[jayanth.devarayanadurga]

He will monitor all the three phases. If any of the phase is OFF then he will disconnect the mains power and turn ON the generator.

 

[kabeer02]

So that simply means their will be no under voltage and over voltage control the generator will come on when ever their is failure of main supply?

 

[jayanth.devarayanadurga]

Yes. Kabeer02

@Asabzi2000 are you watching the posts. Reply. kabeer02 is asking something. You have to clarify the doubt.

 

[Asabzi2000]

Yes, Kabeer. The genset am usnig is 3-phase but am using only one of the phases. But how can a phase monitor be installed. Can u help me with a schematic?

 

[kabeer02]

Yes, Kabeer. The genset am usnig is 3-phase but am using only one of the phases. But how can a phase monitor be installed. Can u help me with a schematic?

for the generator or mains supply?

 

[Asabzi2000]

Kabeer, I din't get ur question. Could you come again

 

[jayanth.devarayanadurga]

He is asking if mains is 3 phase or genset is three phase.