zmpt101b frequancy meter

Hey
For my project I use zmpt101b to measure 220 volts AC
I also have to measure the frequency.
I wonder if I should use a transformer-based circuit that starts with a 12-volt bridge and a diode bridge, etc.? Or can I measure using the sensor?

What schematic does the data sheet of the sensor suggest?

zivkl:
I also have to measure the frequency.

Note that the frequency of mains power is more accurate than the ceramic resonator clock of most Arduinos.
Leo..

i could'nt add library of zmpt101b after so many tries but could not find solution .please send me specific zmpt101b module library. or considered it another library please tell me.