# ADE7816 multiple issues while working on EVB

Hi all,

I am using AD7816 EVB to go through the working of IC. While working on it I am facing few issues while interpreting the values coming from IC.

First let me explain you my setup:

1. I am using Rogowski coils(100mV/KA) connected on three channels A,B and C. And voltage from stable source i.e. Ponovo make Relay Test Kit.
2. Voltage = 63v Current = 100A
1. WTHR1 = 0x000002
2. WTHR0 = 0x000000
3. VARTHR1 = 0x000002
4. VARTHR0 = 0x000000
5. PCF_A_COEFF = 0x400CA4 (50Hz)
6. PCF_B_COEFF = 0x400CA4 (50Hz)
7. PCF_C_COEFF = 0x400CA4 (50Hz)
8. PCF_D_COEFF = 0x400CA4 (50Hz)
9. PCF_E_COEFF = 0x400CA4 (50Hz)
10. PCF_F_COEFF = 0x400CA4 (50Hz)
11. DICOEFF = 0xFFF8000
12. GAIN = 0x49(PGA GAIN 2)
13. CONFIG = 0x01 (enable integrator)

My issues:-

1. RMS value conversions factor:-
1. From the data sheet I saw two formulas to convert the RMS raw values into real value
1. Constant = (1/(Raw count/Input value))
2. Constant = (Input/Count)*K
2. I don't know which one to use.
1. Gain Matching:-
1. After reading AN-1152, it is not clear to me how to do Gain matching for Channel A before doing for others channels as it is mentioned use channel A as reference for gain matching.
2. How to do gain matching for Voltage Channel?
3. Is gain matching is same as like calibration of Voltage and Current channel?
2. I am not able to calculate frequency(50Hz) from the conversion formula given in DS. The value of the period register for 50 Hz networks is approximately 5120 (256 kHz/50 Hz) from DS, after putting this value frequency is coming around 30Hz.
1. Formula Fl = (0x256E3)/(period[15:0] + 1), this is not working for me.
3. Angles:-
1. When I give load on two channels only then I will get stable readings from only one channel. After applying load on all channels I am getting stable readings for all three channels. So is there any rule to give load on all channels?
2. If I changes channel A angles and keep B and C angles as 0deg, then I can see variations proportional to change in Channel A values. If I do the same thing with channels B and C, then I am getting constant values from the registers there is no change values with variation.I

I have attached the jumper settings of my EVB.

Your earlier response will be great for me.

Thank You & Regards