Electricity meter question.

Join today to use advanced features! or Login as user: password:   :: lost password
Threaded View
Click Here To Start a New Thread
Page 1 of 4  
1
2 3 > last»
I have one of the relatively modern electricity meters with a digital
display and when I went to read it today to send in the reading, the
display was reading alternately the power consumed and "rEd".
Additionally a red led is permanently on.

The make of the meter is 'Ampy' - Black and about 100 x 150 x 40mm

Can anyone confirm what this means please?

I have recently had a solar PV system fitted which can feed power back
into the grid. The meter was not changed to accommodate this (instead I
have my own generation meter) so I wonder if it is just an indcation
that the meter has tried to run backwards which would normally happen if
someone was trying to fiddle the meter reading but in my case just shows
the Solar PV has been generating more power than I have been consuming.

TIA

Bob

Re: Electricity meter question.
Bob Minchin wrote:
Quoted text here. Click to load it
I know it is bad form to reply to your own posts but it might help someone.

I have found the answer here
http://universalmeterservices.co.uk/store/images/5193.doc

The red light either flashes every 1 watt-hr consumed or stays on
continuously when the power being consumed is below a preset level.

The display flashing rEd is showing "reverse energy detection" which
would normally mean fraudulent use but in the case of power export from
microgeneration schemes (PV, wind etc) is legitimate.

In my case, when the light is on continuously it means that I am
generating more power than I'm using - this is confirmed by the display
reading now being identical to the one I took 8 hours ago.

According to the manual, the meter has a separate register measuring
exported power although the reading is not displayed.

Bob

Re: Electricity meter question.
On Apr 20, 5:10=A0pm, Bob Minchin

Quoted text here. Click to load it
Meter Memory
All the meters data is recorded in a Ferroelectric Random Access
Memory (FRAM) under the control of the microprocessor.  All the kWh
registers are stored in the FRAM and are updated every 1/100 th of a
kWh.  The FRAM is guaranteed for a minimum of 10,000,000,000 write
cycles


WTF?  Core memory?!  8-)

Re: Electricity meter question.
Andy Dingley wrote:
Quoted text here. Click to load it
Yes I found that difficult to credit but I suppose it maybe used to meet
a possible regulatory requirement for N years retention with no power
connected??

Having looked further, I think it is the 10,000,000,000 write cycles
that makes it ideal for this application to cope with the update rate.

Bob

Re: Electricity meter question.
On Apr 22, 4:00=A0am, Bob Minchin
Quoted text here. Click to load it
Not quite core, but not completely unrelated and quite interesting
http://en.wikipedia.org/wiki/Ferroelectric_RAM

Re: Electricity meter question.
Quoted text here. Click to load it
It's been around for quite a while. FLASH and EEPROM are mostly
useless for this type of application. Given it's an electric meter
they could just use low power SRAM with a super cap backup supply.

MBQ

Re: Electricity meter question.
Man at B&Q wrote:
Quoted text here. Click to load it
Too easily corrupted. Fe RAM has indefinite data retention after removal
of power, better than 10^^15 write cycles, and a glitch during writing
won't corrupt the rest of the data (According to the makers...)

--
Tciao for Now!

John.

Re: Electricity meter question.
wrote:
Quoted text here. Click to load it
Easily designed around.

Quoted text here. Click to load it
You would struggle to "corrupt the rest of the data" with any
technology.

MBQ


Re: Electricity meter question.
Man at B&Q wrote:
Quoted text here. Click to load it
To use one example meter I know of, in what was an empty shop for three
years, how would your idea cope with a couple of years of disconnection?

Quoted text here. Click to load it
I must remember to tell the makers of my cameras that. They tell me
under no circumstances must I take the batteries out while it's writing
to the card, as that may render the card useless.

--
Tciao for Now!

John.

Re: Electricity meter question.
wrote:
Quoted text here. Click to load it
OK, so go back to using FRAM.

Quoted text here. Click to load it
My point stands.

The warning, "may", is due to potential corruption of the card's file
system that isn't designed to be robust enough to withstand corruption
of a single critical memory location. The data is still there if you
have the right tools to recover it.

MBQ


Re: Electricity meter question.
Man at B&Q wrote:
Quoted text here. Click to load it
Not always, IME, but you may have been luckier. Luckily, the camera with
a problem was one used by a member of a group, so they just swapped
pictures.

--
Tciao for Now!

John.

Re: Electricity meter question.
Quoted text here. Click to load it
FAT filesystems can't be made safe in this way because they require
multiple sector updates to be made simultenously, to remain self
consistent. They have a common delayed action corruption mode where
you can read all the data OK after an interrupted operation, but latent
inconsistent spacemap update results in data corruption sometime
later on when the filesystem is written to again. Also, because there
are so many different implementations of FAT filesystem drivers which
do things in different orders and may not use the clean shutdown bit,
it's not easy to spot this without doing something like a full chkdisk
operation, which appliance devices usually don't implement, nor have
the time to do.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Re: Electricity meter question.
On Tue, 17 May 2011 12:55:31 +0000, Andrew Gabriel wrote:

Quoted text here. Click to load it
Can you explain? If they are built with one FAT, I can't see why that
would be so, although there might be some free block loss.

--
Use the BIG mirror service in the UK:
 http://www.mirrorservice.org

We've slightly trimmed the long signature. Click to see the full one.
Re: Electricity meter question.



Quoted text here. Click to load it
You never worked with bubble memory did you?


Re: Electricity meter question.
Quoted text here. Click to load it
It was actively worked on where I used to work, but not personally,
no.

I was thinking of more modern, mainstream, technologies, not dead
ends.

MBQ

Re: Electricity meter question.


Quoted text here. Click to load it
It had some interesting faults.
I killed the development of bubble memory cards on SystemX by designing
something far better to replace them.
Cheaper, more reliable and five times as fast tends to kill the competition
rather well.
Its still in use now and its more than a decade (or two) old.


Core memory [was Electricity meter question]
[sorry for incorrect threading and I hope I got the original attribution
correct, I've only got half the thread visible]

Andy Dingley wrote:

Quoted text here. Click to load it
Build your own 32bit core store for an arduino

http://www.corememoryshield.com/report.html



Re: Core memory [was Electricity meter question]
On Sun, 15 May 2011 08:57:08 +0100, Andy Burns wrote:

Quoted text here. Click to load it
Yup, saw that on sparetimegizmos recently. I do actually have a piece of
antique core - 512m bytes from an Atlas machine!




--
Use the BIG mirror service in the UK:
 http://www.mirrorservice.org

We've slightly trimmed the long signature. Click to see the full one.
Re: Core memory [was Electricity meter question]
Bob Eager wrote:

Quoted text here. Click to load it
If you fancy 'knitting' some more £25 for 45,000 ferrite rings

http://cgi.ebay.com/300556183278


Re: Core memory [was Electricity meter question]
On Sun, 15 May 2011 10:28:48 +0100, Andy Burns wrote:

Quoted text here. Click to load it
That would be bad enough if I had two eyes! As it is....

--
Use the BIG mirror service in the UK:
 http://www.mirrorservice.org

We've slightly trimmed the long signature. Click to see the full one.
Threaded View
Click Here To Start a New Thread
Page 1 of 4  
1
2 3 > last»

Site Timeline