[ADE9000] How to calculate physical(real) value with xRMS value?

Question asked by ghsung on Oct 30, 2017
Latest reply on Dec 1, 2017 by Gary.Kang.AnalogDevices

Hi, I'm the user of ADE9000 evaluation board.

I'm stuck how to get real physical value with xRMS value.

For your information, I connected 2 line- live and neutral line to VAP and VAN respectively to test single phase output, 220V. And I also connected IAP and IAN to each line of CT sensor(1000:1) respectively.

A hole of CT sensor is linked to the neutral line of 220V.

And I got the RMS value at the RMS window of ADE90xx evaluation software.

Here's the value.

- AIRMS : 224,817 decimal (PGA_IA : x1 / ADC_REDIRET_IA : 7 / AIGAIN : 0 / AIRMSOS : 0)

- AVRMS : 33,908,007 decimal (PGA_VA : x1 / ADC_RED_VA : 7 / AVGAIN : 0 / AVRMSOS : 0)

- Full-scale ADE code of xRMS : 52,702,092

I think it's right way to calculate with CONVERSION CONSTATNS but i don't know how to calculate IFSP and VFSP.

Referring to the SYSTEM PARAMETERS, the IFSP value needs burden resistor value, voltage divide resistor value, V nominal, I nominal, CT ratio etc. However I have no idea how to calculate with is value especially current transfer function and voltage transfer function(Vrms/Arms).

- V nominal = 220Vrms

- I nominal = 0.27Arms

- Frequency = 60 Hz

- CT ratio = 1000:1

- Burden resistor = 10Ω * 2 (20Ω)

- Voltage Divider = ?? (I didn't customize ADE9000 eval board, so the R7A, R8A, R9A value would be 330kΩ, but it dropped 220kΩ when I connect VAP and VAN pin to live and neutral line. It's so weird. Did i connect wrong?)

Please let me know how to solve this problem.