frequency of refreshing

Good morning,

Does anyone know the frequency of refreshing the values of the “power” variable?

I think it's about 2 times per second, but do you have more details.

Also, how do I know when this value has just been updated so I can read it right after.

Thank you in advance for your information

In fact I'm trying to know at what frequency (how many times per second) the ESP8266 will read the power values in the ADE7953 in the EM shelly.

In my case, I use the Shelly EM for power control, so I need to know the responsiveness of the Shelly EM.