Hi Russell,

Thanks for your reply, I am working on my ISR code to make it more clean and tidy I will get rid of the RMS calcualtions from the interrupt and put it in the main program. I will post the new code and results as soon as possible.



I am using P89V51RD2 in 6 clock/cycle mode with a 8MHz crystal. You are right I am using pulse transformer since it is a big thryristor driving inductive loads. It is....
P89V51RD2 --> BC557 --->opto 4N35 ---> TIP122 [ power transistor ]----> Pulse Transformer ----> Thyristor.

I will also work more on the filtering issue in order to improve my system.

Thanks & Regards,
Prahlad Purohit