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ADE7758 - From current transformer to Rogowski coil

Question asked by Faustin on May 6, 2015
Latest reply on May 9, 2015 by hmani

Hi everyone,

 

I am currently working on a wattmeter using the ADE7758 for energy metering.

The ADE7758 is configurated and calibrated for Current Transformer on the current channel and it is working fine.

 

However, I want to use a Rogowski Coil (di/dt current sensor) instead of classic Current Transformer.

As the datasheet says page 17 (http://www.analog.com/media/cn/technical-documentation/data-sheets/ADE7758.pdf), I added another low-pass filter before the current input of the ADE.

 

But when I want to measure the current signal with the Rogowski Coil, there are no values going out from the ADE7758 (both in current and voltage). Is it rather a hardware (I roughly added the SMD low-pass filter on my ADE circuit, but the connections are fine) or a software problem ?

 

And if it is a software problem, is there any other register or configuration that I need to change compared to when I use a Current Transformer ? Apart from the integrator which I activated (0b10000000 on gain register 0x23).

I just need the ADE7758 to get current and voltage values for the time being, I do not need these values to be accurate for now (offset, phase, ...)


Also, I tried to do the measurement with the Rogowski Coil and the hardware configuration I use for Current Transformer (so with just one low-pass filter but without the burden resistor), and it is working of course, but the values are not accurate because the ADE7758 is calibrated for Current transformer signal, and it would be good to compare the accuracy of measurements between the ADE circuit with one LPF, and the ADE circuit with two LPF.


I hope I was clear, and thank you in advance for any help.


Regards,

 

Faustin.

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