Re: [rrd-users] Energy Metering (Was: Modifying results for GPRINT

Alex van den Bogaerdt wrote:

>I may be asking for help myself soon; I'm thinking about a
>webcam, a led (for illumination) and some ocr software to
>read my own meters. That, or a smarter idea on how to automate
>reading those meters.

I assume then that you still have the old =

mechanical "Ferraris Disk" meter. I would look to =

see if there's any way you could focus a sensor =

on the disk which will have some markings on it - =

IIRC there are lots of stripes around the edge =

(high frequency, high resolution) and some larger =

markings (such as one/revolution). Ideally you =

would like to mount a reflective sensor close to =

the disk surface, but your utility supply company =

will not be amused if you break the seal and =

start fiddling with their meter !

If you could achieve this then you'd have just =

the same system as the OP - one pulse every X =

number of watt-hours.


Or ...

WARNING - DO NOT try this without adequate knowledge/training !

It may be simpler to install your own private =

meter downstream of the main meter. All it =

requires is to drop the tails out of your =

distribution board, put new tails from your meter =

to the board, and put the original tails into the =

supply side of your meter.

A quick look around gives a number of suitable =

units, generally in the region of =A3100-=A3150 (or =

something like =A4150-=A4220).

Even simpler would be to get a meter unit that =

has an external CT (current transformer) and use =

a split CT - ie one with a core that splits into =

two pieces so it can be put around a cable =

instead of having the cable threaded through it. =

That would eliminate the need to disturb your =

main cables at all as the unit can take it's =

voltage feed from an output circuit from the =

distribution board, and the CT can be clipped =

around a main feed cable without disconnecting it.


If you REALLY want to DIY it (and have the skills =

to do it without killing yourself or burning the =

house down), then there are chips to allow you to =

build your own. See =

http://www.analog.com/en/subCat/0,28...255F0%255F,00=
..html, =

and in particular =

http://www.analog.com/en/prod/0,2877,ADE7753,00.html =

which does all the complicated stuff and has a =

serial port !

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