I am using ADE7858A for my application. ADE7858A is interfaced with an microcontroller over I2C protocol. I have connected AGND, DGND and neutral together. I was bit worried about these connections and have following questions:-
1.) Is it ok if I don't connect AGND and DGND together.
2.) In case if anybody interchanges phase and neutral connection and it might lead to damage of all the components like microcontroller and other ic. How can i protect my circuit from wrong connection.
In 3 phase 4-wire Wye configuration, you use CTs for current sensor, that will do a isolation for high common mode voltage, and you should connect ground to Neutral wire, but you can't connect ground to the Phase wire. And in this situation, if your ADE chip and the MCU are working by the same power supply, that's OK. And the MCU and chip are working on the Neutral wire or the ground wire, there will just be 3.3V(power supply) voltage high, there is no need for isolation. For single phase application, if you connect ground to Phase wire, the application can be found in AN639, I sent you the link before. When you work in this single phase system, as you connect ground to Phase wire, the chip is working on the Phase wire, if you connect the power and ground to the MCU, the MCU will also work on the Phase wire, and this will be dangerous to anyone who touch the meter. That's why you need to do the isolation, in common the MCU will work in the earth ground, and you shouldn't supply the power from ADE chip to MCU directly. In another single system like connect ground to Neutral wire, then you can use CT on Phase wire to detect current, and CT can do the isolation, so you don't need to do the isolation with ADE chip and MCU. Thank you very much.