Where to buy energy meter ??

Post by **brandtz** » Mon Feb 12, 2007 12:46 pm

Hi,

I do not have either time, or enough competence, to put together hardware to get energy meetering into my computer, is there really noone out there selling ready made, just to plug in, units for this??? (I understand it has to be done close to the mains incoming, and can not plug it into any outlet in the wall, such things I do understand...

What I would need is something that can give me computer ready data (ex.: RS232 with application to read it, 1-wire perhaps?) for each of the three phases and the "instantaneous" energy consumtion. If it also could give aggregate over some predefined time period it would also be great.

If this does not exist at the moment, I would say it must be a really interesting unit to develop and start producing. IF that is the case, anyone in this fora that are interested (with electronical skills enough) to help me define it? I have the integration and production contacts for it!!

Looking soo forward to any comments that you would have on the above.

Reagards
Lars

Post by **Bwired** » Mon Feb 12, 2007 2:38 pm

Hi Lars
Rfxcom has a ready made powermeter check this topic http://www.domoticaforum.eu/topic.asp?TOPIC_ID=174 you can also the site for more info www.rfxcom.com. All the other energy readers on this forum are self made.
Regards
Pieter

Post by **brandtz** » Mon Feb 12, 2007 3:41 pm

Hi,

Thanks, I had seen that already but think that is seem much too complicated and expensive. And....Since those units only clamp on one of the three incoming lines, would it really be able to show correctly (I saw the 3% rate..) if there is an imbalance between the lines??

If this is the best ready made I guess I need to start soldering my own....Are there any kits out there for those ??

Lars

Reagards
Lars

Post by **b_weijenberg** » Mon Feb 12, 2007 5:49 pm

Hi Larz,

There is a kit available at http://www.microchipdirect.com/ProductS ... =MCP3905EV
But if you add the cost of the CT and the RF transmitter to it you pay a lot more then the RFXPower. And you also need to have the competence to write the firmware in the transmitter and configure the Microchip power measurement design.

The installation of the RFXPower requires you to put a connector in a wall socket and clamp the CT on a power cable. Connect an RFXCOM receiver to an USB interface and you can receive the RFXPower (and X10 and Oregon Scientific weather sensors)

There will be always an imbalance between the 3 power lines. Therefore you will need for each phase a measurement device like the RFXPower.

The accuracy of 3% is close to what a standard utility meter does. The high accuracy is possible because the voltage and the amperes are measured and a real power usage can therefore be calculated correctly.

Bert