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Topic: Using CST-1020 (Read 3 times) previous topic - next topic

RIDDICK

-Arne

Nunov


If you really want to measure energy accurately, you are far better off using a device specifically
for this purpose like a ADE5569.
http://www.analog.com/en/analog-to-digital-converters/energy-measurement/ade5569/products/product.html

It does all the hard work for you.


Hi.
Thanks for your suggestion.
I got and ADE7763 ( http://www.analog.com/static/imported-files/data_sheets/ADE7763.pdf ) to help me out to compute the power and energy, but this chip is supposed to receive a voltage between 0.5v and -0.5v.
How am I supposed to reduced a 230V RMS to 0.5 V? Using a voltage divisor? Am I getting any good resolution with such low voltage?

RIDDICK

#22
Oct 21, 2012, 09:37 pm Last Edit: Oct 23, 2012, 08:40 am by RIDDICK Reason: 1
welcome back Nuno!  :)

According to the datasheet (page 12 of 56, figure 22) a voltage divider is a good idea...
but use sufficiently big resistors, so that u dont waste more energy than necessary...
they say 600kR+1kR is good for 110V...
for 240V u can use 1MR+1kR, i guess...
maybe u need to adapt the capacitor?
maybe u can just omit the capacitor (just in case ur load distorts the voltage...)?  ;)

i dont know why they use transformers so often in this forum...
a voltage divider seems to more natural and easier...
maybe it is about isolation... if u use a voltage divider the meter has to share the ground/neutral line...
-Arne

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