# How the F1 and F2 will change if the meter constant is not 100imp / KWh in ADE71056

Hi Sirs,

I would like to ask how to calculate the F1 and F2 in case the meter constant to 1600 imp/ kWh ? The calculation in the datasheet is given for 100 imp /kWh but it is not shown how to adapt to other

meter constant value.

Thank you.

Parents
• Hello,

f1 and f2 drive a counter typically. There is a fixed division from cf output to f1 and f2. 128,64,32,16,2048

so for example if cf max is:

scf =1 22.4Hz and s1=s0=0 the max freq on f1 and f2 is 22.4/128=0.175hz

scf = 0 11.2hz  and s0=s1 the max freq on f1 and f2 is 11.2/64 = 0.175hz

You need to know the counter you are going to use to determine the imp/KWH needed for F1 and F2. Not sure why you would need 1600 ipm/kwh on f1 and f2. The example is for cf output 1600 imp/kwh and f1 f2 100 imp/kwh.

If you are using a micro to count pulses. I would use the cf pin instead if F1 and F2. https://www.analog.com/media/en/technical-documentation/application-notes/AN-679.pdf

Dave

• Hello,

f1 and f2 drive a counter typically. There is a fixed division from cf output to f1 and f2. 128,64,32,16,2048

so for example if cf max is:

scf =1 22.4Hz and s1=s0=0 the max freq on f1 and f2 is 22.4/128=0.175hz

scf = 0 11.2hz  and s0=s1 the max freq on f1 and f2 is 11.2/64 = 0.175hz

You need to know the counter you are going to use to determine the imp/KWH needed for F1 and F2. Not sure why you would need 1600 ipm/kwh on f1 and f2. The example is for cf output 1600 imp/kwh and f1 f2 100 imp/kwh.

If you are using a micro to count pulses. I would use the cf pin instead if F1 and F2. https://www.analog.com/media/en/technical-documentation/application-notes/AN-679.pdf

Dave

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