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ADE5169 evaluation software and ADC conversion

Question asked by renatinha on Dec 18, 2015
Latest reply on Apr 6, 2016 by dlath

Hello, I'm trying to use ADE5169 evaluation software to read some energy values. I connected the current and voltage source properly to the chip and I used an oscilloscope to visualize the analog inputs. They seem ok (the circuits are correct too). However, I can't read a value that means a thing to me. So I did a search at Analog Device's site and discovered that I have to callibrate the sensor. I tried to do it using AN-950 and UG-061 instructions, but evaluation software doesn't allow me to write registers at energy metering section. So I wrote at those registers using the section Direct Read and Write to SFR/RAM, and it worked. I tried to read and do the same at energy metering section and it was the same, I couldn't do nothing using that section (also, the evaluation software always stop working for no reason, and I have to open it up again and again). The problem is, even if I can read and write (directly or indirecly) registers at SFR/RAM register, I don't know how to interpretate the huge value that appers when I read VRMSx or IRMSx registers. So I went back to ADE5169 datasheet.

At page 59, Voltage Channel RMS Calculation section, it says that the equivalent value of the full-scale ac signal (or 0.5V) is approximately 0d1,898,124 (0x1CF68C) in the VRMS SFRs and the conversion from the register value must be done externally in the microprocessor using a V/LSB constant. First thing I have done was to look Voltage Channel ADC section at page 51 (as datasheet sugested) and I didn't understand how the conversion is done and how I can get the  volt value. Also, I searched for V/LSB constant and how its calculed and I found nothing, just a small text at AN-950, wich I didnt understand (even if I understand, how can I use this value to get volt value?). The main question is: If I know that 0.5 volts is represented by 0x1CF68C (according to page 59), how do I convert this value back to volts? I think It's related to Analog Devices Sigma delta ADC (I will read AN-282 note to see if I get an idea), but right know I am stuck.

PS: Is there another program that I can use to callibrate ADE5169? when I was reading AN-950, appears that exists a software only for callibration purposes (page 11 and 12), but I couldnt find this software.

Thank you so much,

Renata

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