When I built my house 10 years ago, I used magnetic latching relays to control the ceiling lighting (extensive) throughout the house... The room use a simple bell transformer to put 24V AC to all the switches with light weight 20 gauge wiring back to the relay panel...

The advantages are no high voltage on the switch wiring and switches...
Small gauge wire (brown jacketed 3 wire telephone wiring) running to the switches...
It is easy to add or remove switches for any given light circuit... The 20 porch lights (wrap around veranda) have 5 switches placed throughout the house that will turn them on/off... (Draw that one out and calculate the amount of 12 gauge wire it would need for a conventional three way switching circuit)...
Controlling of lights is made easy.  For example:
By using a simple counter and a timer I have the ability of panic lighting - that is, flip any light switch a few times in the correct pattern and all the lights in the house come on or off (except bathrooms and closets)...
I can have exterior motion detector lights and the driveway sensor also turn on one or more interior lights as a warning, or convenience -  that circuit is turned off at the moment as the coons and feral cats keep turning on the bedroom lights at 3 AM!
At the time copper was cheap and the relays expensive, so I didn't save any money... Today would be another story...

The disadvantages (well, I haven't found any), but the electrical inspection was fun... The house inspector came in harumphing, puffing his chest, and generally acting officious...
" Well, let's see.", he says as he steps into the mud room...  He bent over and inspected a duplex outlet... The grounds were properly attached, etc., per the NEC,  etc...
"Humph.", he says...
He stood up and his eyes focused on the control panel with row after row of magnetic latching relays, and the complicated looking wiring diagram glued to the panel door...
"What's that?", pointing with a slightly trembling finger...
"Magnetic latching relays."
"What's it for?"
"Remote control of house lighting.. It's tied to the smoke detectors and motion sensors to turn on all the house lights if there is an alarm."
He stood in silence for a long minute staring at the rows of gleaming relays... Slowly he walked over to the clipboard hanging on the wall... Pulled out his pen and signed the ' approved' box on electrical inspection sheet, and walked out without saying another word... Inspection over...

Now, what about digital control for boat circuits... The issue I see here is not the install or the savings, but the maintenance... When the bilge pump refuses to turn on while you are frantically stabbing the 'on' button - as the sea pours in through the broken hose - how is Joe Boater going to trouble shoot it? Does he have an oscilloscope to see if the master controller is generating the correct digital code to that device?  Is the decoder at the pump relay gone bad?  Is the wire to the decoder broken?  Is the wire to the switch broken? Is the relay itself bad?  So many questions, so little time!
I am not afraid of technology and I have more background in electronics than most, but I see digital control as having the severe handicap of making Joe Boater dependent upon being within shouting distance of a service center at all times...  Until the makers show either 100% reliability come hail or sea water, or a foolproof method of bypassing a broken computer, it is not ready to go offshore...

denny

How low will we go? Check out Yahoo! Messengers low  PC-to-Phone call rates.

-----Original Message-----
From:Dennis OConnor
Now, what about digital control for boat circuits... The issue I see here is
not the install or the savings, but the maintenance... When the bilge pump
refuses to turn on while you are frantically stabbing the 'on' button - as
the sea pours in through the broken hose - how is Joe Boater going to
trouble shoot it?

REPLY
Valid point. My system and all the good systems I have looked at has a
manual over-ride that forces the circuit ONorOFF as the case requires. When
my associate and I reviewed the design parameters this was number on on the
list of must have features.

I agree that service could be a problem until most yards gain familiarity
with the concept and the system.
However if the troubleshooting is reduceed to identifying which ciurcuit is
malfunctioning, has a manual over ride and service consist of plugging in a
spare relay as a first line repair; then even a mecahnic can deal with it.

AS I see it one of the biggest short-comings with today's technology is the
lack of decent documentation by the manufacturers. Its almost like they are
afraid of telling the customer how the system works.
The system I hand built back in 1996 was left in the care of diesel
mechanics and a high school dropout who was good with car steroes. That was
the sum total of their electronic technical expertise.
In spite of this several years later the shop formenan reported that this
system had the lowest maintenance of any of the 12 system I had designed and
installed for that company.

When Voltaire first developed the Leyden jarI'msure people toldhimit was
highly impratical.  The modern equivalent is anything but fragile.

Cheers

Arild

-----Original Message-----
When the bilge pump refuses to turn on while you are frantically stabbing
the 'on' button - as the sea pours in through the broken hose - how is Joe
Boater going to trouble shoot it?
denny

REPLY
If that criteria was applied strictly to every piece of equipment installed
on a boat we would still be using kerosene lights, wood and leather hamd
bailers and sails for propulsion.

Electric bilge pumps already fail for any number of reasons, including plain
old neglegt, old age, corrosion or plain old debris in the pump impeller.
Yet people stil go to sea with that equipment.

AS I said in the beginning, the concept lends itself to varying degrees of
sophistication. Denny explained how he used latching relays for a non
computerized system. Excellent approach! It still reduced the amount of
wiring and added flexibility to the system which is a big justification for
using it.

As for reliability.  The average car owner doesn't worry themselves sick
about a possible breakdown  when they comtemplate a drive through open
country in broiling desert heat or freezing blizzards.
you don't see cars stranded every couple of miles because the driver is not
an electrical engineer.
yet most modern cars have exactly this same system onboard.

For the most part cruisers who make extended sea voyages are self reliant
and have a better than average  skill at trouble shooting with basic tools
like a DVM. How many boat now go to sea with only GPS and electronic chart
systems for navigation? How many boats now carry a sextant, sight reduction
tables and a properly corrected magnetic compass as their primary navigation
tools?

Denny wrote:
I see digital control as having the severe handicap of making Joe Boater
dependent upon being within shouting distance of a service center at all
times...  Until the makers show either 100% reliability come hail or sea
water, or a foolproof method of bypassing a broken computer, it is not ready
to go offshore...

denny

REPLY
In the first place, have you bothered to examine in detail the existing
systems and seen how they do provide redundancy in control?  Have you looked
at how the manufacturer has made provision for quickly dealing with damaged
control modules? If you haven't, then your presumption of unreliability is
founded on speculation not the actual equipment.
When companies like Teleflex or Hughes spend millions in R&D the results are
much more than just a breadboarded experiment built in someone's garage.
Proof of concept has come and gone several decades ago. Companies that now
offer systems are striving to present products that address the real world
possibility of failures in the same way any other electrical or electronic
equipment does.
What product does have 100% reliability under every imaginable situation
with an unlimited time guarantee?

regards
Arild

Sounds like  NMEA2000 http://www.nmea.org/pub/2000/index.html

All good points, like you said, if you've got replacement relays and local manual override, that goes a long way.  Also, these systems are simple enough that each owner should be able to have a cheap pendant that can plug in anywhere it it will read out what is going on.

This subject recently came up during a discussion on another forum during a discussion of the diesel-electric systems from OSSA which uses a power/data bus type control systems( http://www.ossapowerlite.com/index.htm).  This stuff started out for industrial control, we used it on a couple prototype spacecraft in the late 80's.  It's since made it's way into the consumer market.  This is common in cars nowdays and is called CanBus (Controller Area Network Bus).  Below is a response I got on application of this technology in the marine market.  (attached at the end).

As an aside there was an article in a recent SEA magazine about the use of LED and other lower power lighting in boats to bring the total required system capacity down.  But as you pointed out, if you are running a main line capabable of running a windlass, low power lighting doesn't dramatically reduce the required wire gauge.

"Hello Mark,

Can Bus technology is alive and well and slowly but surely creeping
it's way into the recreational marine market.

The National Marine Electronics Assoc several years ago realized
that their comm protocol NMEA183 was outdated and adopted a new
standard NMEA2000. This is Can Bus based and is "open architecture"
where anyone who wants can connect compatible hardware to the "bus."
Mercury Smartcraft is a leader, but their comm is proprietary and
they will only play with their friends.

Teleflex with their "Magic Bus " and Lowrance Electronics along with
Simrad and Airmar transducers are leading the electronic accessory
manufacturers in Can Bus and Blue Seas and Cole Hersee along with
Faria instruments and several others are leading the wiring devices
manufacturers in this area.

Most of the major engine manufacturers also have adopted either NMEA
2000 or their own proprietary system for "fly by wire" or both.

I am most familiar with the  Lowrance system as I helped develop a
NEMA 2000 interface  for Bennett trim tabs that would allow tab
position indicators on a Lowrance compatible
chartpoltter /fishinnder/multifunction display. Tab controls will be
the next development. The Lowrance system will also allow engine
instrumentation display the same way, they can currently display
Suzuki outboard information for example.

Starting very soon, more boats will have just a few wires routed
through the boat carrying electronic signals that will run
everything from blowers to nav lights as well as engine control,
instrumentation and steering. www.nmea.org  for more, click on NMEA2000 info.

Arild Jensen elnav@telus.net wrote: -----Original Message-----
When the bilge pump refuses to turn on while you are frantically stabbing
the 'on' button - as the sea pours in through the broken hose - how is Joe
Boater going to trouble shoot it?
denny

REPLY
If that criteria was applied strictly to every piece of equipment installed
on a boat we would still be using kerosene lights, wood and leather hamd
bailers and sails for propulsion.

Electric bilge pumps already fail for any number of reasons, including plain
old neglegt, old age, corrosion or plain old debris in the pump impeller.
Yet people stil go to sea with that equipment.

AS I said in the beginning, the concept lends itself to varying degrees of
sophistication. Denny explained how he used latching relays for a non
computerized system. Excellent approach! It still reduced the amount of
wiring and added flexibility to the system which is a big justification for
using it.

As for reliability.  The average car owner doesn't worry themselves sick
about a possible breakdown  when they comtemplate a drive through open
country in broiling desert heat or freezing blizzards.
you don't see cars stranded every couple of miles because the driver is not
an electrical engineer.
yet most modern cars have exactly this same system onboard.

For the most part cruisers who make extended sea voyages are self reliant
and have a better than average  skill at trouble shooting with basic tools
like a DVM. How many boat now go to sea with only GPS and electronic chart
systems for navigation? How many boats now carry a sextant, sight reduction
tables and a properly corrected magnetic compass as their primary navigation
tools?

Denny wrote:
I see digital control as having the severe handicap of making Joe Boater
dependent upon being within shouting distance of a service center at all
times...  Until the makers show either 100% reliability come hail or sea
water, or a foolproof method of bypassing a broken computer, it is not ready
to go offshore...

denny

REPLY
In the first place, have you bothered to examine in detail the existing
systems and seen how they do provide redundancy in control?  Have you looked
at how the manufacturer has made provision for quickly dealing with damaged
control modules? If you haven't, then your presumption of unreliability is
founded on speculation not the actual equipment.
When companies like Teleflex or Hughes spend millions in R&D the results are
much more than just a breadboarded experiment built in someone's garage.
Proof of concept has come and gone several decades ago. Companies that now
offer systems are striving to present products that address the real world
possibility of failures in the same way any other electrical or electronic
equipment does.
What product does have 100% reliability under every imaginable situation
with an unlimited time guarantee?

regards
Arild

Power-Catamaran Mailing List

I hope that consideration has been made of the likelihood
of High Frequency (HF) signals on the vessel of 150 Watts
or greater from Marine SSB or Amateur Radio equipment!!

I know that 100 Watts at 3.8 MHz makes my ABS light
on the dash of my GMC picku light up when I transmit.
It never goes out even when transmissions stop.  The
only way to return the ABS system indicator to normal
is to shut off the engine and restart.

D C "Mac" Macdonald
Another Adventure
Grand Lake - Oklahoma

----Original Message Follows----
From: Mark mark424x@yahoo.com
Reply-To: Power Catamaran List power-catamaran@lists.samurai.com
To: Power Catamaran List power-catamaran@lists.samurai.com
Subject: Re: [PCW] Lightweight electrical systems - NMEA2000
Date: Tue, 25 Apr 2006 16:03:58 -0700 (PDT)

Sounds like  NMEA2000 http://www.nmea.org/pub/2000/index.html

All good points, like you said, if you've got replacement relays and local
manual override, that goes a long way.  Also, these systems are simple
enough that each owner should be able to have a cheap pendant that can plug
in anywhere it it will read out what is going on.

This subject recently came up during a discussion on another forum during a
discussion of the diesel-electric systems from OSSA which uses a power/data
bus type control systems( http://www.ossapowerlite.com/index.htm).  This
stuff started out for industrial control, we used it on a couple prototype
spacecraft in the late 80's.  It's since made it's way into the consumer
market.  This is common in cars nowdays and is called CanBus (Controller
Area Network Bus).  Below is a response I got on application of this
technology in the marine market.  (attached at the end).

As an aside there was an article in a recent SEA magazine about the use of
LED and other lower power lighting in boats to bring the total required
system capacity down.  But as you pointed out, if you are running a main
line capabable of running a windlass, low power lighting doesn't
dramatically reduce the required wire gauge.

"Hello Mark,

Can Bus technology is alive and well and slowly but surely creeping
it's way into the recreational marine market.

The National Marine Electronics Assoc several years ago realized
that their comm protocol NMEA183 was outdated and adopted a new
standard NMEA2000. This is Can Bus based and is "open architecture"
where anyone who wants can connect compatible hardware to the "bus."
Mercury Smartcraft is a leader, but their comm is proprietary and
they will only play with their friends.

Teleflex with their "Magic Bus " and Lowrance Electronics along with
Simrad and Airmar transducers are leading the electronic accessory
manufacturers in Can Bus and Blue Seas and Cole Hersee along with
Faria instruments and several others are leading the wiring devices
manufacturers in this area.

Most of the major engine manufacturers also have adopted either NMEA
2000 or their own proprietary system for "fly by wire" or both.

I am most familiar with the  Lowrance system as I helped develop a
NEMA 2000 interface  for Bennett trim tabs that would allow tab
position indicators on a Lowrance compatible
chartpoltter /fishinnder/multifunction display. Tab controls will be
the next development. The Lowrance system will also allow engine
instrumentation display the same way, they can currently display
Suzuki outboard information for example.

Starting very soon, more boats will have just a few wires routed
through the boat carrying electronic signals that will run
everything from blowers to nav lights as well as engine control,
instrumentation and steering. www.nmea.org  for more, click on NMEA2000
info.

Arild Jensen elnav@telus.net wrote: -----Original Message-----
When the bilge pump refuses to turn on while you are frantically stabbing
the 'on' button - as the sea pours in through the broken hose - how is Joe
Boater going to trouble shoot it?
denny

REPLY
If that criteria was applied strictly to every piece of equipment installed
on a boat we would still be using kerosene lights, wood and leather hamd
bailers and sails for propulsion.

Electric bilge pumps already fail for any number of reasons, including plain
old neglegt, old age, corrosion or plain old debris in the pump impeller.
Yet people stil go to sea with that equipment.

AS I said in the beginning, the concept lends itself to varying degrees of
sophistication. Denny explained how he used latching relays for a non
computerized system. Excellent approach! It still reduced the amount of
wiring and added flexibility to the system which is a big justification for
using it.

As for reliability.  The average car owner doesn't worry themselves sick
about a possible breakdown  when they comtemplate a drive through open
country in broiling desert heat or freezing blizzards.
you don't see cars stranded every couple of miles because the driver is not
an electrical engineer.
yet most modern cars have exactly this same system onboard.

For the most part cruisers who make extended sea voyages are self reliant
and have a better than average  skill at trouble shooting with basic tools
like a DVM. How many boat now go to sea with only GPS and electronic chart
systems for navigation? How many boats now carry a sextant, sight reduction
tables and a properly corrected magnetic compass as their primary navigation
tools?

Denny wrote:
I see digital control as having the severe handicap of making Joe Boater
dependent upon being within shouting distance of a service center at all
times...  Until the makers show either 100% reliability come hail or sea
water, or a foolproof method of bypassing a broken computer, it is not ready
to go offshore...

denny

REPLY
In the first place, have you bothered to examine in detail the existing
systems and seen how they do provide redundancy in control?  Have you looked
at how the manufacturer has made provision for quickly dealing with damaged
control modules? If you haven't, then your presumption of unreliability is
founded on speculation not the actual equipment.
When companies like Teleflex or Hughes spend millions in R&D the results are
much more than just a breadboarded experiment built in someone's garage.
Proof of concept has come and gone several decades ago. Companies that now
offer systems are striving to present products that address the real world
possibility of failures in the same way any other electrical or electronic
equipment does.
What product does have 100% reliability under every imaginable situation
with an unlimited time guarantee?

regards
Arild