Sub-Meter Electricity Monitoring

Dunno about the CU you mention, but since it's a Part P job, you may want to consider getting a sparky to do it and consulting with them. When my CU was redone with various "unusual" items - X10 filters, noise filters, computer ring without RCD etc the sparky just bought an empty CU enclosure, reused some of the bits and cut up bits of bus bar to suit.

I was surveying 1 DIN power meters last night and found some others, it would be interesting to compare the various units, sample interest and consider a bulk buy, I would be up for a handful.

Carlo Gavazzi EM10 http://www.productsonline.info/POL/s...=1199760718843
Inepro ADM1TE:http://www.dmmetering.com/
DRM1005 http://www.pjwmeters.co.uk/product_detail.php?id=28

I think the latter 2 might be the same as the ones you have.

Also found this: http://hepol.manufacturer.globalsour...-KWh-Meter.htm
but looks a bit like a cheapo Chinese clone so can't be sure of quality etc.

I wasn't going to do the CU upgrade myself as you point out this would contarvine Part P. But I do like to know what is available and at what price before getting in the "professionals" who then make lots of sucking air noise!

As for the actual 1 DIN units I have been in touch with a supplier of the ADM1TE units and they would offer a 40% discount for 10 or more units (I need seven) so a bulk buy maybe an excellent idea.

Paul

Received a quote today from another supplier selling the ADM1TE at £25 unit price. This is without any bulk discount.

Under Part P you could do it yourself, but you'd have to notify Building Control and most likely pay for an inspection of the work - at which point most people say what the hell and get a P-ified sparky in. :-)

Sub-Meter Electricity Monitoring

Interesting ... could I check I understand what's going on here, please - ie: each 1-DIN meter would be connected to one input of the Idratek Octal Digital Input module, which would count the pulses & keep track of the time without involving / tying-up Cortex, but be always-ready to send the information to Cortex on-request ... ... is that right ?

Not sure how the costs pan-out, presumably these meters are cheap enough to have many of them, rather than a few that are switched about (by Idratek) at intervals ?

Will you be using them to not only track power-usage, but also to provide feedback on how things are working (eg: might be able to use one to track progress of a dishwasher cycle, or immersion heater, etc) ... to improve system reliability ?

'find myself again wishing Idratek had a Serial I/O module ... for added options & versatility !

These power meters have the current fed through them, they are in the mains path, so you wouldn't be moving them about. The max rating is 32A, typical ring main rating, so you have a meter module per ring (effectively one alongside every MCB) for each circuit you want to monitor.

I believe that Cortex now supports the pulse counting capability on any digital input, so doesn't have to be an ODI, eg if you have some DIN rail modules in a sub-junction box you could monitor there.

Cortex can then present the result (ie translated into kWh etc) in the usual fashion.

I guess if there is sufficient power discrimination it might be possible to track a large user, but might be difficult to separate washing machine from oven or toaster, for example. It would be an interesting experiment!

Rather than a serial IO module I'd prefer some kind of logic object in Cortex that attaches to an IP port and can be configured to interpret protocol and parse values out. Since there are many Ethernet serial IO devices out I think this would have more flexibility. This was actually how I was hoping the xPL integration would work.

Sub-Meter Electricity Monitoring

Thanks ... rather than moving them about, 'was thinking of using relays, and choosing times of low-current to switch ... probably unnecessarily complicated !

'like the idea of a logic object on an IP network port ... must make sure we put-in enough Cat-5e - experience on other things tells me to treble my current estimate of what we need, I might just double it ...

Chris,

I think what you are after is a current sensor?

I haven't found one yet that is small enough and would interface into Idratek. I have thought about making one myself to at least detect when say the washing machine finishes its cycle and the current drops to near zero. Idea being that Cortex could then send a message that the washing machine needs emptying or the extractor fan shuts off 5 minutes after the tumble-dryer cycle ends.

To monitor actual energy usage is more complicated because you have to measure current and voltage at the same time to accurately calculate watts (things like transformers and motors)

Paul

David,

Funny you should say that about Part P inspection as I came across a local company today that just do inspections rather than installs. However, as you point out it maybe just as easy to get a sparky in to do it. I'm going to ring round a few local ones and see if any are intrested.

Paul

I know the thread's about sub meter monitoring - but how would one go about monitoring entire usage? My thought was to physically connect some sort of photodiode arrangement to the front of the led flashing in my meter, and then count pulses from that. Or am I missing something obvious?

Jon,

You certianly could do just what you have described and someone has written a web page on how to do this with 1-Wire:



In the sub-metering as described with 1-DIN units Cortex can also show a cumulative collection for total house usage as well as individual readings per ring-main.

Paul

Sub-Meter Electricity Monitoring

AH also had a thread on this maybe a year ago ... inconclusive, though, IIRC ...

presumably pulse-counting doesn't tie Cortex up - or does it ??

Nope, don't believe it does from what I remember with chats with Vivian and Karam. The ODI and other digital interfaces can count locally and then package the information together in a network package for sending to Cortex.

Paul

Slightly off-topic but .....

Hmmm, I was looking at that thinking that looked like a fairly neat & accurate way to find out how much power our house uses over time - it's small and only has one ring main and two lighting curcuits so monitoring things individually might be overkill.

And then I went off at a complete tangent. The downstairs of our house is all open plan so there are no doors for Cortex to monitor to tell if people are moving from room to room so you have to rely on the PIRs triggering, but looking at the kit this project is based on (the Velleman IR Light Barrier http://www.velleman.be/be/en/product/view/?id=342937), I started wondering if you could use that to create a "virtual doorway". When the beam is broken you tell Cortex a door between the rooms has been opened same as you do with a reed swtch for a physical door. Could do the same thing with the stairs as they open directly onto the living room and at the moment you can't tell if someone is going from the living room upstairs until they trigger one of the upstairs PIRs. If you placed one on the lower steps you could tell someone was going upstairs almost immediately.

What's people's opinion - do you think it would work ?

Jamie