Carrier current communication on Low voltage/high current AC

On Fri, 10 Jun 2005 23:28:24 -0400, the renowned Mike Monett
<no@spam.com> wrote:

Spehro Pefhany wrote:

[...]

Well, if I have to mess with 2.x GHz, I'll just slap a Zigbee or two
in there and be done with it.

Best regards,
Spehro Pefhany

LOL! Sometimes it pays to post. Thanks - I was not aware this product
existed.

Seems simple and attractive. Any reason you prefer to not use it?

Mike Monett
Click to expand...
It's perhaps an appropriate application for the technology (low power,
low speed signalling/data transmission), but the toolchain and so on
is pretty involved for a one-off. Here's the RF section- as you can
see, it's dead simple. All the RF smarts are in the IC design (the
small one at the top, of course, the larger QFP is a micro).

http://www.speff.com/zig_rf.jpg


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
On Sat, 11 Jun 2005 01:04:20 +0000, Rich Grise wrote:

On Fri, 10 Jun 2005 16:49:29 -0700, John Larkin wrote:
...
There are people in this ng who brag about their ability to deliver
calibrated insults to their customers' intelligence, and further
complain about being unemployed.
...

There are those who say, "The Customer is Always Right, Even When
He's Wrong!"
Click to expand...
No, the customer is not always right, but he's always the customer.

<snip>

--
Keith
 
On Sat, 11 Jun 2005 10:50:21 -0400, the renowned keith
<krw@att.bizzzz> wrote:

On Sat, 11 Jun 2005 01:04:20 +0000, Rich Grise wrote:

On Fri, 10 Jun 2005 16:49:29 -0700, John Larkin wrote:
...
There are people in this ng who brag about their ability to deliver
calibrated insults to their customers' intelligence, and further
complain about being unemployed.
...

There are those who say, "The Customer is Always Right, Even When
He's Wrong!"

No, the customer is not always right, but he's always the customer.

snip
Click to expand...
Except when you decide to fire him.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
On Sat, 11 Jun 2005 12:25:00 -0400, Spehro Pefhany
<speffSNIP@interlogDOTyou.knowwhat> wrote:

On Sat, 11 Jun 2005 10:50:21 -0400, the renowned keith
krw@att.bizzzz> wrote:

On Sat, 11 Jun 2005 01:04:20 +0000, Rich Grise wrote:

On Fri, 10 Jun 2005 16:49:29 -0700, John Larkin wrote:
...
There are people in this ng who brag about their ability to deliver
calibrated insults to their customers' intelligence, and further
complain about being unemployed.
...

There are those who say, "The Customer is Always Right, Even When
He's Wrong!"

No, the customer is not always right, but he's always the customer.

snip

Except when you decide to fire him.
Click to expand...
Yeah. Sometimes the culture is such an obvious mismatch that you just
have to walk away, even when the deal would be mutually beneficial. My
biggest problem is usually with high-level people, often PhDs, who
just *have* to be smarter than anybody else. Physicists are probably
the worst.

John
 
Hello Fred,

Hmmm- keep thinking and you will eventually discover Bluetooth ( or is
it BlueTooth)- a few billions of industrial serial<->Bluetooth modules
available for the express purpose of replacing or upgrading industrial
communications hard wire with wireless in a way that is transparent to
the control infrastructure.
Click to expand...
Yes, good point. It's just that much of this wireless gear is very
limited in range. It takes a simple obstruction and reception is gone.
Next to our lab there is a wall which contains aluminum backed fiber
insulation. I can't even walk behind there with the cordless phone
without losing the call.

I am afraid ZigBee could be affected as well. If Spehro's solution was
for, say, irrigation equipment and someone places frost cover blankets
over it in the fall this could already block the RF path. Sometimes PLC
is just the ticket.

Regards, Joerg

http://www.analogconsultants.com
 
Hello Mike,

ISM is a good idea, but some bands are better than others. For example,
Diathermy machines may wipe out lower bands, such as 13MHz, and induction
heaters use other bands. These machines can have leads going between the
machine and the load, so there is plenty of opportunity for radiation
leakage.
Click to expand...
Yes, although I found that if you aren't in a heavy industry area and
away from hospitals even 13.56MHz is pretty clean. Out here (east of the
Sacramento burbs) that frequency is open.

The 2.45GHz band may be useless due to interference from microwave ovens.
However, there is a way to use this band without interference.

Since the magnetron only produces power when the anode reaches 4KV, there is
a brief interval at each zero crossing when no maggies anywhere are
conducting.

Just use this to transmit and receive data, and you have the band to
yourself:)
Click to expand...
That's a good idea. But then there are WLAN, cordless phones and so on.

Regards, Joerg

http://www.analogconsultants.com
 
Spehro Pefhany wrote:

[...]

It's perhaps an appropriate application for the technology (low power,
low speed signalling/data transmission), but the toolchain and so on
is pretty involved for a one-off. Here's the RF section- as you can
see, it's dead simple. All the RF smarts are in the IC design (the
small one at the top, of course, the larger QFP is a micro).

http://www.speff.com/zig_rf.jpg

Best regards,
Spehro Pefhany
Click to expand...
It seems ideal for many of the projects I get involved in. Thanks!

Mike Monett
 
Joerg wrote:

[...]

Yes, although I found that if you aren't in a heavy industry area and
away from hospitals even 13.56MHz is pretty clean. Out here (east of the
Sacramento burbs) that frequency is open.
Click to expand...
Things may seem quiet for a long time, then a new company can move in next
door and everything goes to hell. It reminds me of a consulting trip to LA
back in the 1980's. I happened to look out the window during a break and
noticed some people dressed in funny suits wandering around my rental car
making measurements.

I asked my hosts what was going on, and they said the company next door was
working on some kind of linear accelerator for military applications, and I
happened to park in the beam. They were checking to see if the car had become
radioactive. That was 20 years ago. I guess they could melt the car with
today's technology:)

[...]

Regards, Joerg
Click to expand...
Mike Monett
 
John Larkin wrote:

biggest problem is usually with high-level people, often PhDs, who
just have to be smarter than anybody else. Physicists are probably
the worst.
Click to expand...
Don't throw out the baby with the bath water, some of them may really
have something to say.
But most of them talk because they have to say something, of course.

I like the idea someone mentioned, to simply send bits from the cpu to
the mains, with a capacitor as the connection to the mains.

In a 3-phase house short the phases, for the signal frequency, with two
10nF capacitors.

Prepare the message in the memory, and then write it out to the output
port in a steady stream, frequency 100-455kHz.
A simple output stage gives some oompa to the signal before sent into
the mains wiring.

The receiver circuits. Selectivity through LC circuits, or 455 kHz
filters, and amplification, like a simple IF stage in a radio. After
that we have the cpu, which runs at a much higher frequency than the
signal frequency, so we can use the cpu to analyse the received
signals. Use error-correcting code.

Every unit has a number, and adds this number to every message it sends.

A central unit takes control of the system and polls the units.

All units need a cpu, and selectivity receiver circuits, and the power
output stage for transmitting. A high voltage capacitor and maybe other
safety components for the connection to the mains.

To receive the bits we could use a flank sensitive circuit instead of
resonance circuits for selectivity.
The flank sensitive circuit reacts only to flanks within a certain
risetime range.


--
Roger J.
 
On Sat, 11 Jun 2005 12:25:00 -0400, Spehro Pefhany wrote:

On Sat, 11 Jun 2005 10:50:21 -0400, the renowned keith
krw@att.bizzzz> wrote:

On Sat, 11 Jun 2005 01:04:20 +0000, Rich Grise wrote:

On Fri, 10 Jun 2005 16:49:29 -0700, John Larkin wrote:
...
There are people in this ng who brag about their ability to deliver
calibrated insults to their customers' intelligence, and further
complain about being unemployed.
...

There are those who say, "The Customer is Always Right, Even When
He's Wrong!"

No, the customer is not always right, but he's always the customer.

snip

Except when you decide to fire him.
Click to expand...
Then you have no customer. ;-)

Everyone has a customer, even "captives" like myself. I can also fire my
customer, and he me. Until either happens, he *is* the customer
though. ...after I'm a free man. ;-)

--
Keith
 
On Sat, 11 Jun 2005 14:26:35 -0400, Mike Monett wrote:

Joerg wrote:

[...]

Yes, although I found that if you aren't in a heavy industry area and
away from hospitals even 13.56MHz is pretty clean. Out here (east of the
Sacramento burbs) that frequency is open.

Things may seem quiet for a long time, then a new company can move in next
door and everything goes to hell. It reminds me of a consulting trip to LA
back in the 1980's. I happened to look out the window during a break and
noticed some people dressed in funny suits wandering around my rental car
making measurements.

I asked my hosts what was going on, and they said the company next door was
working on some kind of linear accelerator for military applications, and I
happened to park in the beam. They were checking to see if the car had become
radioactive. That was 20 years ago. I guess they could melt the car with
today's technology:)
Click to expand...
....and they let it loose? Yikes! I guess it's a good thing you weren't
living near a medical research facility.

--
Keith
 
Spehro Pefhany wrote:
On Fri, 10 Jun 2005 23:28:24 -0400, the renowned Mike Monett
no@spam.com> wrote:


Spehro Pefhany wrote:

[...]


Well, if I have to mess with 2.x GHz, I'll just slap a Zigbee or two
in there and be done with it.

Best regards,
Spehro Pefhany

LOL! Sometimes it pays to post. Thanks - I was not aware this product
existed.

Seems simple and attractive. Any reason you prefer to not use it?

Mike Monett


It's perhaps an appropriate application for the technology (low power,
low speed signalling/data transmission), but the toolchain and so on
is pretty involved for a one-off. Here's the RF section- as you can
see, it's dead simple. All the RF smarts are in the IC design (the
small one at the top, of course, the larger QFP is a micro).

http://www.speff.com/zig_rf.jpg


Best regards,
Spehro Pefhany
Yeah, Zigbee is nice! Just finished a project using the Freescale
Click to expand...
chips, and it was pretty simple. Freescale is coming out with a chip
that combines their Zigbee radio and the HC processor in a single
package that will really lower chipcount. The big problem is getting
all the protocol stacks set up...

Charlie
 
Charlie Edmondson wrote:

[...]

Yeah, Zigbee is nice! Just finished a project using the Freescale
chips, and it was pretty simple. Freescale is coming out with a chip
that combines their Zigbee radio and the HC processor in a single
package that will really lower chipcount. The big problem is getting
all the protocol stacks set up...

Charlie
Click to expand...
I think they are ideal for some applications. Inexpensive, simple, small,
low power, good data rate, reasonable range, different LAN modes, large
address range, security, multiple vendors... what did I miss?

Thnx, Speff.

Mike Monett
 
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