Microcontroller Based firing angle control of Pic Microcontroller

Hello everyone.I am doing my project Microcontroller based firing angle control of Scr .for this i am using Analog input 0-5volt ,a ZCD as interrupt ..but i am unable to do programming plz help anyone ..i know the logic but i am not able to write the code ..plz help me

Key phrase here: "I am doing my project..."
Translation: "please do my project for me".

Hi,

I'm not writing code.
But you will find people to help you to write your own code.

SCR control.
How is your SCR gate control hardware?
Isolating, or not? If isolating: how? Transformer, optical...?
Do you need pulse trains?
One or two SCRs?
What is the load? Purely resistive, capacitive, inductive.
(In worst case a transformer, which is very critical on trigger unsymmetries, causing DC voltage)
What frequency?
What smallest delay, what biggest delay?
Do you want to build a true regulation, or just a angle control?
Where does your setpoint come from?

In either case.
* you need to detect zero cross. In both directions.
* then you need to start a trigger delay
* generate the firing signal
* switch off the firing signal
* wait for the next zero cross.

Because it is a timing critical application ..i'd use hardware periferal. Capture, (PWM) signal generation, timer/counter, ISR.

This all depends on your used hardware. Therefore you should give us the informatiins.
But I (we) don't want to work through complete datasheets, therefore you should do this.
Best is if you could give all necessary information at once, not piece by piece.

Klaus

Hello sir ,i am usin 4 SCR in bridge configuration.and i have to use both resistive as well as inductive load.
i am using zero crossing detector to create the firing pulse and applied it to interrupt.i am using pic16f877a ic.
to vary the firing pulse i am using a variable pot of 0-5 volts which is applied to analog port.and according to which the firing ange is varied.i tried to do the programming part but i am unable to do it.i made the simulation on proteus 7.sir i need to varying pulse at the output of pic 1should vary during positive half cycle and another should vary in another half cycle.in my simulation i am gettin only 1 pulse.so i need code which can fire 4 SCR simultaneously.if possible help me.

Hi,

you just show some foreign files.
But you should show what you have done so far. And what your ideas are.
(Maybe it´s in the .DSN files, but I can´t open it)

--> You need to show your schematic and you need to show at least your flow chart. And if you have done some coding, the show it, too.

Klaus

Maybe it´s in the .DSN files, but I can´t open it

Click to expand...

...and considering that this file extension isn't supported anymore by the most recent Proteus releases, it gives the strong impression that it is not his own project.