PG&E rececntly installed SmartMeters at my place.
The URL above says it uses RF to communicate. It's easy to see where the electrical meter gets power. Where does the gas meter get power to run electronics?
-- These are my opinions, not necessarily my employer\'s. I hate spam.
They might actually use the flow turning the meter vane to generate power, but my better guess would be a battery-powered RFID tag, that only comes awake between a range of dates and "pings" for a reader, very low consumption between "pings".
I actually have a smart water meter. Since my youngest daughter runs the City of Phoenix Water Labs I'll see if she knows, or knows who to ask.
...Jim Thompson
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I love to cook with wine Sometimes I even put it in the food
Likely the case. I see one spec for a "gas smart meter" from the UK which specifies that the battery life must be "consistent with the asset life of meter under average use profiles", and that 10 years is considered an acceptable asset life.
"Clever synchronisation of transmission intervals and use of components with low power consumption allow very long service lives to be achieved with relatively small batteries."
Their requirements profile shows a continuous current level of 45 uA, a burst of 7.5 mA for 10 ms once every 2 seconds, 25 mA for 4 seconds every 30 minutes, and 25 mA for 50 seconds once a week. I'd guess that the latter is the clock-synchronized "everybody in the neigborhood, wake up and report in!" radio transmission window. Average current works out to 140 uA, and with a service life of 11.5 years this requires 14 amp-hours of current usage (at 3 volts).
It appears that one D-sized lithium cell can provide 19 amp-hours, for a 10-year service life. Service life of the cell can be extended considerably by adding a supercapacitor in parallel, to help provide burst current capability during the latter part of the battery's lifetime.
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I'd guess battery power; and interrogation by the electric meter.
The utilities were all agog over BPL for Internet access, with the "oh, by the way, we can also use it for meter reading & SCADA" part in tiny print on page 43. With its debunking for access, the utilities seem to be looking again at UHF RF for the backhaul.
-- A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that\'s close........[v].(301) 56-LINUX Unless the host (that isn\'t close).........................pob 1433 is busy, hung or dead....................................20915-1433
Correct. The gas and electric meters are independent and don't depend on each other to interrogate. My local utility (PSE) installed these some years ago. They also provide gas service (with the same equipment) in Seattle, where the electricity is supplied by a different utility, who use different technology (people running around reading meters). So the gas meters don't depend on a compatible electric meter nearby.
They did drop my power for a few seconds. The pilot light was a non issue, as the gas meter register can be replaced independently from the meter itself. So it wasn't necessary to shut off the gas.
PSE has their own wireless mesh network in my neighborhood. But the meters are capable of being read by a van equipped with r.f equipment driving down the road where no such mesh exists. No Broadband over Power Lines needed.
-- Paul Hovnanian mailto:Paul@Hovnanian.com ------------------------------------------------------------------ Windows tip #248: add BUGS=OFF to your registry.
Thanks. I thought of batteries, but wasn't smart enough to notice that you could push the battery life out far enough so that you didn't have to replace them routinely.
10 years might be a bit short, but I assume the unilities can work that out. (My previous gas meter was there way over 10 years.)-- These are my opinions, not necessarily my employer\'s. I hate spam.
In some places [such as Balt.] where it's one utility; you might think they'd put the smarts in the electric meter. But I've not seen proof of same.
But a liev backchannel, be it RF or BPL, would get them several things beyond meter reading. First is outage monitoring; rapidly knowing exactly what houses are dark. Second is load shedding. While some do that now with 150 Mhz RF for HVAC loads; I'm sure they'd love to stagger turnons of everything: i.e. bring up an unloaded neighborhood segment, then turn on houses one at a time over a few minutes...
-- A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that\'s close........[v].(301) 56-LINUX Unless the host (that isn\'t close).........................pob 1433 is busy, hung or dead....................................20915-1433
ISTM they rotate out the gas meters every N years anyhow, to test the calibration.
-- A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that\'s close........[v].(301) 56-LINUX Unless the host (that isn\'t close).........................pob 1433 is busy, hung or dead....................................20915-1433
Does that work with a battery powered gas meter? I think the only way you could get decent battery life would be to have it sleeping in ultra-low power mode most of the time with nothing more than a 32KHz alarm clock ticking. You can't have the receiver listening for the truck to come by. You might be able to have all the receivers in a neighborhood timed to go off at 3PM on the last Thursday of the month and arrange to have a truck there at the right time.
I assume the electric meter doesn't have any power when the power is off. I suppose you could add a supercap with enough energy for a handful of exchanges. (Power died, power still dead, power back.)
In my case, there is no provision for controlling anything. All they did was replace the meter in an old house with a new meter.
The staggered turn-on could be done without a back channel. Just have each meter pick a random number. No big deal if two end up being close together. It's still a lot nicer than the whole place turning on at the same time. (You still need the switch.)
-- These are my opinions, not necessarily my employer\'s. I hate spam.
Why bother? The meter is polled every minute; Big Brother keeps a log. When a buncha meters stop chirping, guess why...
True, but that's now. Next year, maybe...
True. But what I was thinking was it defaults to powering up with the loads off. It immediately reports in, and is told to wait xxx seconds before turning on the unspecial loads. Only after a few more minutes would the HVAC and water heater be brought on.
If it never reached Big Brother, have it wait randomly then power up the house.
They'll want power control for another reason, I bet -- to turn off delinquent accounts.
-- A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that\'s close........[v].(301) 56-LINUX Unless the host (that isn\'t close).........................pob 1433 is busy, hung or dead....................................20915-1433
Two problems: 1) The network that does the polling might go dead as well. If a few nodes go dark and, as a result, meters beyond that point can't be interrogated, the power co. has no idea whether they are on or off. 2) My power company doesn't know where their meters are. They think mine is about 10 miles from where it really is. So they know my power is off, but they can't associate that with neighboring outages.
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And this corner case is worse than the current system how?
Must be hard to get your meter read!
-- A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that\'s close........[v].(301) 56-LINUX Unless the host (that isn\'t close).........................pob 1433 is busy, hung or dead....................................20915-1433
Maybe, with N being in the 25 to 75 (years) region. That may have to change thanks to new smart meters.
exactly
turnons
turn
Every minute? not a chance in hell.
What crap, it would only have whole house/apartment/residential unit on/off. Appliances with that kind of smart are still a ways off.
Why do you spew the most unrealistic crap here?
At least around here, the utilities now offer load-shedding discounts. Sign up, they put a 150 Mhz controlled box in the control/power feed into your HVAC and/or electric water heater.
It would be trivial to put some local X-10's or other technology controlled device at the main breaker panel instead.
Why, clearly just to annoy you...
Utility workers hate to go on disconnect calls; they get threatened, assaulted and worse. Further assuming the homeowner pays up, then there's a 2nd visit for the restoral.
-- A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that\'s close........[v].(301) 56-LINUX Unless the host (that isn\'t close).........................pob 1433 is busy, hung or dead....................................20915-1433
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