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Energy meter ADE7755/68 with 8051

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JeffreyPeter

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I read about ADE7755 and understood its calculations. I am not clear about the Counter section and interfacing with microcontroller.
If I designed an energy meter with 3200 imp/kwhr, should I count 3200 pulses for 1 kWhr ?
Thanks in advance...
 
The way I read it is if you read a frequency of 2500 then the power is 2500 imp/kwh.. simple as..

You don't have to count that... you can deduce the frequency in 1 second... They recommend 2 seconds to be accurate..

I may be wrong..
 
I actually have 3200 impulse/Kwhr as meter constant. Does it mean - 3200 pulse from CF pin = 1 Kwhr ... ?

Like I said... The way I read it is.. If you have 3200 impulse / Kwh, then CF will have a frequency of 3.2Khz...

You just need to measure the frequency... The text also said that the frequency on the CF pin is a tad unstable so sample for a minimum of 2 seconds

If you count 6400 pulses per two second period and divide by 2... 3200 or 3.2Khz.
 
How to measure the frequency in 8051 pls explain a bit more... In some design I found the sampling at 10 sec what does it mean..
 
From datasheet,
Average Freq = Counter/ timer
=> 6400 counts for 2 sec => 6400/2 = 3200
Energy = Counter/timer * timer
=> 3200 * 2 = 6400.
for our meter 3200 imp/kwhr so 2 kwhr...

I am not sure about this calculation... what if I get less counts.
for example count = 20 for 2 sec.
Then how should I proceed with the calculation to get energy ??
pls correct me if Im wrong..
 
From datasheet,
Average Freq = Counter/ timer
=> 6400 counts for 2 sec => 6400/2 = 3200
Energy = Counter/timer * timer
=> 3200 * 2 = 6400.
for our meter 3200 imp/kwhr so 2 kwhr...

I am not sure about this calculation... what if I get less counts.
for example count = 20 for 2 sec.
Then how should I proceed with the calculation to get energy ??
pls correct me if Im wrong..


It also said... [LATEX]Energy = Average Power * time = \frac{Counter}{time} * time = Counter[/LATEX]

So Doesn't that mean that the counter represents Watts?
 
Yes It should be in watts... As meter constant is 3200 imp/kwhr, can't I count 3200 pulses from cf and account for 1 kwhr ?
 
I still reckon that 3200 = 3.2khz = 3.2KWh..... I may be wrong but thats what I'm seeing..

You'll need to experiment with a know source.... Take a 40 watt bulb and measure that... see what the frequency is.... if its 40hz then you'll know..

I was also looking at this..

Here are some simple examples:

I have a 100 watt light bulb on my front porch that is turned on approximately 5 hours every evening. I am paying about $1.59 a month on my electric bill.

100w X 5 hrs = 500w divided by 1000 = .5 kWh every evening. Multiply by 30 days/month.
.5 kWh X 30 days = 15 kWh a month.
15 kWh X 10.6 cents (.106) = $1.59 a month on my bill. (About 5 cents every evening).

I have a 12 cup coffee maker that is on approximately 2 hours every morning. The label on the bottom of the coffee maker reads 7.5 amps, 120 volts. To find the watts you multiply amps X volts, 7.5a X 120v = 900 watts. I am paying about $5.72 a month on my electric bill.

900w X 2 hrs = 1800w divided by 1000 = 1.8 kWh every morning. Multiply by 30 days/month.
1.8 kWh X 30 days = 54 kWh a month.
54 kWh X 10.6 cents (.106) = $ 5.72 a month on my bill. (About 19 cents every morning).

We have a 3.5 quart slow cooker (crock pot) that we will use on average about 8 hours, 7 times a month to prepare dinner. The label on the bottom reads 120 volts, 190 watts. The amount of watts is already given, no need to figure it out. I am paying about $ 1.13 a month on my electric bill or .16 each meal we prepare. Certainly an economical way to prepare dinner.

190w X 8 hrs = 1520w divided by 1000 = 1.52 kWh each meal. Multiply by 7 meals/month.
1.52 kWh X 7 meals = 10.64 kWh a month.
10.64 kWh X 10.6 cents (.106) = $ 1.13 a month on my bill. (About 16 cents a meal).
 
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