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ADE9078 RMS readings not changing

Question asked by MarinusS on Jul 23, 2018
Latest reply on Jul 26, 2018 by MarinusS

Using the ADE9078 I found that the VRMS and IRMS registers do update on small I=500mA and V=10V input values.

I simulate these values with an OMICRON simulator.

 

For current CT1000:1 with R=180Ohm burden res.

For Volt resistor divider = 150x.

 

So on 500mArms input, I measure 0.09Vrms at input pin.

And on10Vrms input, I measure 0.066Vrms at input pin.

 

With the inputs above I get readings of VRMS=3297683 and IRMS=6654074, and these values updates every time I run the debugger on the PIC33 through SPI.

But if I change the input to the following values:

 

1Arms input, I measure 0.18Vrms at input pin.

63Vrms input, I measure 0.42Vrms at input pin.

 

Then the VRMS and IRMS values update about 3 times and then it stays the same, so every time I read the value in the register it stays the same, even if I change the input values (Vin and Iin).

 

I'm sure I'm still within the input voltage range of the chip as to not saturate the input pins.

My setup as follows:

 

1. Write 0x00000000 to xIGIAN, xVGAIN and xPGAIN registers.

2. Write 0x0010 to ACCMODE register, 3-wire delta, 50 Hz

3. Write 0x00117514 to VLEVEL register.

4. Write 0x00000000 to CONFIG0, . Set ININTEN=0 , INTEN=0

5. Write 0x0000 to WFB_CFG, 0x0000 Set bit 9&8 to 00 

6. Write 1 to RUN register

7. Write 1 to EP_CFG register

 

I then watch for DREADY bit in STATUS0 register.

 

Any help will be appreciated.

 

Marinus

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