Need to measure High Voltages with microcontrollers

[Shahzad73]

Hello

I want to design a interfaces which can measure domestic or business main power supply. I need a interfaces which can give information like current Voltage, current or Load. I will use a microcontroller which will read the current information of the usage of power supply with some interval (user defined) and store them in EPROM or send them to computer through RS232 or parallel port. The software on the computer will analyze and store these information in database so that any one can view it later.

I am good in designing digital system using micocontrollers but not in designing analog interfaces.

What I want to do is that design a system which can be installed at any domestic or business location and it will archive the usage of electricity.

I can also partner with some one on the net and produce the product jointly so if some body is interested please contact me so that we can work jointly and develop this product.



Shahzad Aslam
Shahzad73 at hotmail.com (replace at with @)

 

[Oznog]

Well, I don't have experience, but I can see 4 ways:
1. Voltage divider: simple but I don't think there's enough isolation, there's too much reliance on ground.
2. Separate the ADC's Vdd and GND from the rest of the system, follow the AC ground, and of course use a voltage divider, and use an optoisolator for serial com. This is almost certainly the best option.
3. Use transformers to get voltage & current. Non-sinusoidal waveforms will be distorted.
4. Use induction devices to detect voltage and Hall induction devices to measure current. The DC value of either waveform is virtually unreadable, though there should be none in normal operation. It might distort nonsinsoidals as well, I don't know. It's expensive too, but does have the neat ability to clamp around conductors without having to disconnect anything.

 

[kentken]

Take a look at maximwww.maxim-ic.com/ They just came out with some measuring ic's, take a look and see if any of them will work for you.