spaco wrote:
> Will wrote:
>
> > Does anyone make power meters that allow the usage data to be collected
> > centrally and graphed over time? I am NOT looking for panel meters. I
> > want meters that either replace a wall receptacle or will act as a PDU
> > plugging into a wall socket. The application is power metering across each
> > device within a building, in order to determine which devices are eating up
> > the most energy.
> >
> > I need to be at or under $200/meter, a bit more than that if the device is a
> > true PDU.
>
> Try www.dataq.com. I see input devices ("amplifiers" or
> "conditioners") for about $89 each that can sense what you say you want.
> That leaves you 2 grand for the DAU plus software. I see DAU's with at
> least 16 inputs. Should work out okay with your $200 per receptacle
> budget. If you have some electronics expertise, you should be able to
> do the "conditioning" stuff yourself.
> If all the receptacles are 120 volts, then all you REALLY need is to
> measure current. Even if some are 220, you already know that THAT'S
> always going to be 220, so you still need only measure current, letting
> you analysis software multiply the appropriate voltage. If you are
> really fussy because of some highly inductive loads, you need to measure
> KVARS, etc. and you are on your own.
If Pete's device can deliver the data in digital form, you should
be able to grab capture it using a "one-wire" net for analysis,
plotting, etc.
I'm working on a subsystem for capturing other energy data (sun
brightness, airflow, and temperatures) using this approach - and
so that I don't have to dedicate a PC to the task, I'm using a
tiny NSLU2 to monitor the one-wire net and record to CF (compact
flash) cards. The NSLU2 has ethernet capability, so if you wanted
to periodically download the collected data to a PC it'd be quick
and easy.
If this sounds "sorta like" what you'd like to do with power
readings, you're invited to follow the link below to see how easy
it really is. And yes, the cost should be considerably less than
$200 per node.
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/Projects/Monitor
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>
> > Does anyone make power meters that allow the usage data to be collected
> > centrally and graphed over time? I am NOT looking for panel meters. I
> > want meters that either replace a wall receptacle or will act as a PDU
> > plugging into a wall socket. The application is power metering across each
> > device within a building, in order to determine which devices are eating up
> > the most energy.
> >
> > I need to be at or under $200/meter, a bit more than that if the device is a
> > true PDU.
>
> Try www.dataq.com. I see input devices ("amplifiers" or
> "conditioners") for about $89 each that can sense what you say you want.
> That leaves you 2 grand for the DAU plus software. I see DAU's with at
> least 16 inputs. Should work out okay with your $200 per receptacle
> budget. If you have some electronics expertise, you should be able to
> do the "conditioning" stuff yourself.
> If all the receptacles are 120 volts, then all you REALLY need is to
> measure current. Even if some are 220, you already know that THAT'S
> always going to be 220, so you still need only measure current, letting
> you analysis software multiply the appropriate voltage. If you are
> really fussy because of some highly inductive loads, you need to measure
> KVARS, etc. and you are on your own.