Electricity Monitoring - How I do it

[lvrouter]

Electricity Monitoring - LED Displays

You can download LED "images" from: Digit Mania (http://www.digitmania.holowww.com/index.html). There are hundreds of them. I have "tweaked" some of their images to add special characters (: . , etc) and can upload them here if you like some specific set of images. I am partial to the yellow ones that look slightly italicized.

In the ASP code where I want to display a specific value I use something like this:

<td align=center>
<%=ConvertDigitsF(FormatNumber(CurrentUsage/1000,3))%>
</td>

The "ConvertDigitsF" function looks like this:

Function ConvertDigitsF(intTemp)
    Dim strTemp, strTemp1, strTemp2, intCount
    strTemp = intTemp
    If strTemp="" Then strTemp="0"
    If len(strTemp) < 3 then strTemp = String(3-len(strTemp),"0") & strTemp
    For intCount = 1 to len(strTemp)
        strTemp1=mid(strTemp,intCount,1)
        If strTemp1 = "." Then strTemp1 = "period"
        If strTemp1 = "," Then strTemp1 = "comma"
        If strTemp1 = ":" Then strTemp1 = "colon"
        strTemp2=strTemp2 & "<img src=/images/" & strTemp1 & "7seg.gif>"
    Next 'intCount
    ConvertDigitsF = strTemp2
End Function

Hope this helps, let me know if you need more.

[keef]

Thanks lvrouter.
I looked high and low through all the docs for ChartDirector and just could not figure it out.

PS: I made some green LED displays for some of of my pages.

Thanks again
k

[mb02155]

Code for graphs

lvrouter,

Have you had a chance to post your code to do the graphs (I may just be missing them).

Thank you very much for sharing!!!

[Pnord]

lvrouter;
BEAUTIFUL chart page. I bought some CT's from this guy.

http://www.uplandtechnologies.com/index.html

and am currently trying to get the output into a secu-16.
It's coming along in baby steps.
Thanks for the inspiration.
Paul

[Stevech]

for my US home with two-phases entering the breaker box, plus neutral... can I put one of these current transformers on the neutral and see the sum of the two phases' currents? (I suppose not, I suppose they're out of phase on the neutral).

[drozwood90]

Wow, this is some GREAT stuff!

Man, so many projects, so little $$ and time!!!

--Dan

[WayneW]

no, measuring the neutral in a split phase system is not accurate since there are probably multiple 220V devices that don't put any current on the neutral

[piperpilot]

lvrouter,

Would you mind posting your code on how you do the 24hour chart and the Power Demand History? I finally got my database update code working and am now putting together my ASPX pages...would love to see how you generate those graphs...again...very pretty!

PiperPilot

[TeleFragger]

so is there a way in the us to do this stuff?
we have 2 - 120v legs and 1 neutral coming to our houses.... id like to do this.......same as gas and water.. I can add a water meter in the house to do this.... and same goes for gas.. but electric would be nice...


also anyone know of any links that will work with this stuff where you can buy your own water and gas meters?
I could put one in the house and one where im going to put a sprinkler system in......

[fran_joel]

You can do it a number of ways. To do it from scratch I would use clamp-on ammeters and voltmeters circuits (one set for each phase) that I could read from a computer using a serial multi-channel A/D board (isolated from the mains somehow (very important for safety reasons))

Once you have that data, you can use simple math to calculate the instantaneous power consumption (watts) and your cumulative electrical consumption (watt-hours)

The instantaneous power (watts) consumed on each leg of the power supply is roughly the voltage times the current for each phase (given that residential power factors are usually very close to 1) and the total instantaneous power would be the sum of both phases.

If you plot this data using time as the horizontal axis, then the surface under the curve is your electrical consumption in watts-hours or kilowatt-hours.

If you want to have good accuracy using this method, however, you have to sample the voltage and current fairly often (once every 10 seconds would probably yield very good results).

Joel

[Rupp]

so is there a way in the us to do this stuff?
we have 2 - 120v legs and 1 neutral coming to our houses.... id like to do this.......same as gas and water.. I can add a water meter in the house to do this.... and same goes for gas.. but electric would be nice...


also anyone know of any links that will work with this stuff where you can buy your own water and gas meters?
I could put one in the house and one where im going to put a sprinkler system in......

Here's a link to the kit most users here are using.
http://www.wingsnwakes.com/index.php

[TeleFragger]

Here's a link to the kit most users here are using.
http://www.wingsnwakes.com/index.php

OUCH.. bit out of my price range!!!
thanks for the link...
im the po-hobbiest

[fran_joel]

There is no way cheap way to do it I think.

The RFXCOM solution is not that pricy considering what it does...

Joel

[Pnord]

Frag, if you're interested in DIY solutions check out this guy.

http://www.edcheung.com/automa/ha.htm

He's got some fun ideas.

Paul

[hult]

There is no way cheap way to do it I think.

The RFXCOM solution is not that pricy considering what it does...

Joel

There may be no "cheap way", but there are less expensive ways in my experience .. ;-)

There are also ways that use UL-listed components in the AC entrance ("breaker") panel and are therefore potentially compliant with the National Electrical Code (NEC).

But the RFXCOM solution may not be NEC compliant based on the information on the CheaperTronics web site:
http://www.wingsnwakes.com/product_d...=66&item_id=27


The current transformer used by RFXCOM appears similar/identical? to the Magnelab SCT-0750

http://www.magnelab.com/docs/sct-0750.pdf

that I use in my setup and which _is_ UL-recognized and is clearly so labelled (but not readily visible once installed).
http://www.ECOntrol.org/150A_CTinPanel.jpg

But no certification label is shown on the picture of the RFXCOM transformer and there is no mention of UL listing.

If I were spending $435 + shipping to measure only two AC lines (yikes!) I'd make durn sure that the current transformer was UL-recognized. I might even run it past the local inspection agency first to see if the Authority Having Jurisdiction (AHJ) over the NEC would/will approve it. The meter and the entrance panel are the places that inspectors and utilities are justifiably most concerned about safety and code compliance and are typically very visible.

YMMV ... Marc ( Don't take your electrical advice from a geologist ;-) ... but do be on the look-out for off-spec East-Asian knockoffs of US components.)