I use 1600 samples per second. That gives me 16 samples in each half-cycle of 50Hz mains, and it can read the mains voltage accurate to 0.1V using a 12-bit A/D.
Are you using continuous conversion mode, and the alert/ready pin to determine when to read the new data?

It is in the default mode and the I am not using the alert pin. Is it necessary? I am able to get a pretty consistent reading now based on the variance equation.

 

It is in the default mode and the I am not using the alert pin. Is it necessary? I am able to get a pretty consistent reading now based on the variance equation.

Hi, It is working and I can get a pretty consistent reading. But if I increase the number of samples (to take mean) in the for loop (for(i=0; i<250; i++) readadc()), the watchdog timer is getting reset. I think it is because the time to get a reading from the ads1115 is too long. And the waiting time to get the reading is too long, around 30 seconds or so (after taking mean). Is there any way to solve this problem?