Question
I am looking at the ADE7816 for measurement of 6 CT inputs.I see that IAP, IBP and ICP have fully differential inputs but IDP, IEP and IFPshare a reference.How do AD recommend hooking up the three shared CT's?
Answer
With respect to the current inputs using CT’s, we recommend connecting one leg of each CT output directly to GND so that they are all at the samepotential. Then the IAN, IBN, ICN and IN inputs all have their own R-C filter connected to GND. The other end of each CT output will then beconnected through the anti-aliasing filter to IAP, IBP, ICP, IDP, IEP and IFP. This insures that all channels are identical even if 3 of the channelsare full differential.
A good reference is the Test Circuit in Figure 22 of the Data Sheet.