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Hi,

as far as i have understood from searching maximum post on energy meter forum and your product there are only few ics which measure harmonics distortion, one series is ADE7978 with ADE7932/ADE7933/ADE7923 and another is ADE7880. Is it correct

1- Can you please let me know the difference between these series except isolation?

2- I want to measure single phase 50Hz 90V-440V, 0.01A-10A AC with 0.5% accuracy, is it possible to do that if yes with what accuracy level? and with which series?

I know i need to  step down the voltage into desired range of IC input and need to use shunt / CT for current measurement.

3- at multiple location it is said the dynamic range of 500:1 or 1000:1. what does it mean exactly. say for example in my case, should i calculate the Dynamic range = 440V / 90V = 4.9 (in my case for voltage). or it will be

Dynamic range = (Vmax X 100) / (2 X accuracy x Vmin) = 500 (in my case for voltage).

4- Will it get total harmonic distortion of voltage and current separately or i will get harmonic distortion separately say upto 63? and in second case from where i will found it?

5- Is it possible to measure DC with high ripple with any of these IC?

6- why i can't use the shunt for measuring current with ADE7880?

Sorry, i know that i have put many question in single post, but it was just to save TAT.

with regards,

Ankush

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• Hello Ankush,

We specify in the ADE7880 datasheet 2000:1  0.2% active energy, so if you use a CT and select a burden to make your full-scale 353mv RMS at 10 amps and you go down to 10ma that is 1000:1 so the energy performance will be <0.2%. Now if you set your burden to 50% dynamic range for transients your 10ma range would now be 2000:1 effective dynamic range with 10A at 2:1 at 2000:1 your energies would still be < 0.2%.  Now at 2000:1 to achieve 0.2% the effective energy dynamic range is 2000 / 0.2%  or 1E6:1 for energies. This measurement will have noise so the longer you accumulate the more repeatable the measurement. As a note when using CF the averaging is automatic. The ADE7880 will output a CF period 1000 times longer at 10ma than the pulse at 10 amps.

This example will work for the RMS dynamic ranges.

Does this help?

Dave Smith