Experience with bus based power systems?

[Nordic Cat]

I am considering the use of a so called "smart" power distribution system for a new catamaran build, and would like to know if there are any systems out there that someone can reccomend.

I have done a rough estimate on the weight savings, and it comes to around 40-50 kgs.

The one that tops my list at the moment is this one:

http://www.capi2.com/

Any feedback would be much appreciated.

Alan

[CDK]

Siemens proposed the bus system for passenger cars in the mid-80's but had very little success. Car makers kept on using the conventional wiring harness because it is cheaper, reliable, easy to understand and test.
Only very recently the system can be found in several cars because with anti-theft circuits, air bag control and digital injection the environment has changed to such an extend that a bus system isn't scary anymore. Service tools for all passenger cars are diagnostics computers now, the mechanic with just a test lamp has been phased out.

Using such a system in a boat is something else.
The main drawback is that except steel barges, boats do not conduct electricity so they do not provide a Faraday cage. The bus system runs from the stern to the bow and acts as a large antenna that picks up electrical discharges from thunderstorms, marine radio's and radar.
Of course it is possible to design and install a reliable system, but it requires a skillful engineer and high quality materials. Inadequate shielding or improper grounding will be the cause of failures.

At the present, the average marina technician does not have sufficient education and equipment to install and service such a system.

[Nordic Cat]

Thanks CDK. I think what you are referring to is probably CAN-bus which was developed by Bosch see: http://en.wikipedia.org/wiki/Controller_Area_Network

As far as I can see, the NMEA2000 bus is also a CAN-bus. It should offer "plug and pray" between products from different suppliers. To my understanding, it is not for power distribution. Volvo and others have been using this for some time now.

I fully agree with you that NO mechanic out in the marine industry is likely to be able to help you if something goes wrong.

The bus system I am asking about is solely for Power distribution. IMO it should not be too difficult to work around if problems arise. It's a bit like the mains supply out on the street that goes into each house. As long as you have your cable thicknesses and fuse sizes right it should be safe.


BUT, what should I look out for?

Alan

[lazeyjack]

ca you tell us whata BUS system is? please

[Nordic Cat]

Hi,

I found this very interesting blog by Nigel Calder, reccomended reading for anyone interested in the subject.



http://www.maloyachts.se/Blog/tabid/195/EntryID/14/Default.aspx


Alan

[Nordic Cat]

ca you tell us whata BUS system is? please

LJ,

have a look at the capi2 link I posted in post#1.

If it is not clear, then please ask again....

Alan

[lazeyjack]

ah Qui, bon, can you find a schematic, cos I do not see one here,
sounds interesting, I usually witre all our boats, then get an A.C. registered electrician to sign it off, I find wiring to be very saisfying, and relaxing, makes a change from all those hard work parts of the boat

[Nordic Cat]

ah Qui, bon, can you find a schematic, cos I do not see one here,
sounds interesting, I usually witre all our boats, then get an A.C. registered electrician to sign it off, I find wiring to be very saisfying, and relaxing, makes a change from all those hard work parts of the boat

Here's a link to the PDF with all the technical stuff...

http://www.capi2.com/downLoads/NewCapi2Fine.pdf

I reckon it will save lots of time, cabling and maybe some money, as I have no idea on pricing. They claim weight savings of 50%, but even 30% is a lot of time and money...

Let us know what you think

Alan

[lazeyjack]

ok, Alan , will look at it tomorrow, got a new project ready to build
thanks

[CDK]

All bus systems use callers/listeners or masters/slaves with TTL-level (5V) signals or something like RS232 with 12V signals.
Electromagnetic discharges from nearby thunderstorms put spikes on the signal lines that are a 1000 times larger, so there must be serious over-voltage protection and shielding, otherwise the whole system is permanently damaged before you can even hear the rumble.

There is a street light in direct view from our house, on a wooden pole with the supply cable hanging high in the air. It needs to be replaced after EVERY thunderstorm within a few miles radius.
The ones in the city perform much better: they have underground cables and metal lamp posts. Only a direct hit somewhere in the grid kills them.

[lazeyjack]

thannks Both very interesting

[Nordic Cat]

All bus systems use callers/listeners or masters/slaves with TTL-level (5V) signals or something like RS232 with 12V signals.
Electromagnetic discharges from nearby thunderstorms put spikes on the signal lines that are a 1000 times larger, so there must be serious over-voltage protection and shielding, otherwise the whole system is permanently damaged before you can even hear the rumble.

There is a street light in direct view from our house, on a wooden pole with the supply cable hanging high in the air. It needs to be replaced after EVERY thunderstorm within a few miles radius.
The ones in the city perform much better: they have underground cables and metal lamp posts. Only a direct hit somewhere in the grid kills them.

Not all Bus systems are voltage based, many industrial systems use a current loop like RS 485. Others use some kind of Manchester coding for the physical layer of the OSI structure.

These systems are not as sensitive to voltage spikes, but generally all bus systems need to be wired and grounded correctly, and require skill to be used.

Alan

[lazeyjack]

THE nodes which are just breakers
They need be accessible So if say you have 25 circuits, that means 25 of these nodes, need to be placed in accesible places
I usually use BEP switchboards using breakers I have gone a bit overboard often using a separate pair for each and every light circuit, when I should really have just looped them, apart from the nav , which has to be on separate wire
I wonder how certifaction would see this
one thing I do see, is the saving in weight
But having everything on one ac/ and one dc board, seems more convenient to me?
google up BEP marine, in NZ

[CDK]

Not all Bus systems are voltage based, many industrial systems use a current loop like RS 485. Others use some kind of Manchester coding for the physical layer of the OSI structure.

These systems are not as sensitive to voltage spikes, but generally all bus systems need to be wired and grounded correctly, and require skill to be used.

Alan

I stand corrected. Completely forgot the 20 mA current loops used for industrial communication and sensing. And the old telex of course.

A far superior bus control system for marine applications would be an optical one. Optical fiber is very cheap and light, doesn't corrode and is not prone to electrical fields. Each node has a photodiode and a LED to emit the signal to the next node. The last one gets a return line to the control panel to report the status of all previous nodes.
Might be an interesting project..... but what am I talking about, I'm retired.

[Nordic Cat]

THE nodes which are just breakers
They need be accessible So if say you have 25 circuits, that means 25 of these nodes, need to be placed in accesible places
I usually use BEP switchboards using breakers I have gone a bit overboard often using a separate pair for each and every light circuit, when I should really have just looped them, apart from the nav , which has to be on separate wire
I wonder how certifaction would see this
one thing I do see, is the saving in weight
But having everything on one ac/ and one dc board, seems more convenient to me?
google up BEP marine, in NZ

I would put a node in each "room" as a kind of master switch for that room, and then run out to the individual lamps or whatever. Say 4 in each hullfor lighting etc. 1 for refrigeration, 1 for charger, 1 for instruments, 1 for comms equipment, 1 for winches, 1 for nav lights etc...

All linked to the main control panel, which is programmable, so that you can switch any section you want from this panel.

Anyway that is what I envisage, but not having tried it yet, was looking for some experience/feedback.


Alan

[goboatingnow]

despite Nigel Calder writing about it everywhere, I cannot see the advantages of distributed power systems for yachts say under 80 feet. Its full of single point failures, completely impossible to repair at sea, requires a technical sophistication that most users don't have, Its one thing to loose a radio or an instrument, its another to have a whole electrical system go down

I come from a background in industrial electronics, and I cannot see the advantage say in the capi system of having the switching nodes near the load. IN practice there isn't a "huge" amount of wiring in a boat and its mostly star based anyway. The requirement to run a fairly heavy duty power bus means lots of expensive cable running around the boat.


IF somebody wants to go this way, then conventional wiring with smart circuit breakers is the way to go. This are replacements for conventional breakers but allow current monitoring and hence programmable trips and PWM operation etc. This gives all the software advantages that calder rabbits on about but allows the units to be substituted with conventional circuit breakers in the event of system wide malfunctions. ( with some loss of functionality of course).

I just cant see any advantages to these fully distributed systems , none that are safe anyhow

[BigCat]

Nigel Calder is very smart, no doubt much smarter than I am. I'm not smart enough to use this system. Even Nigel Calder had 4 man days of consultation when installing this system. There are a couple of thousand USD spent right there. Rewriting software because you put in another lighting fixture? No thanks. IMHO, if there is a simple way to do something, that's the way to do it, especially on a boat.
Simple is low tech, reliable, cheap, and easy to trouble shoot and repair. Who needs tech problems while fighting off a lee shore in a gale? Not me.

[Nordic Cat]

Please keep your comments coming. I plan to go and have a look at this stuff sometime soon, so your comments give me good questions.

As I work with bus based sensor systems, I'm not too intimidated by the programming part, if the interface isn't too geeky to use. Being able to rewire to a traditional breaker/fuse in case of problems is a must.

Alan

[goboatingnow]

I think that using electronic circuit breakers/relays like http://www.e-t-a.com/uk_ssrpcs+M59d7f67440d.html for example can provide all the advantages of a computer controlled power system with the ability to go back to simple circuit breakers if required. ( or just back up each unit with a parallel manual breaker and remove the electronic one in the case of major failure. This gives all the advantages of calders system ( short and open detection , PWM operation , current sensing etc) without the requirments and failure modes of a bus based system

[Landlubber]

Nordic Cat,

I am currently doing my homework on building a 120 foot displacement boat for a local fella, he is into Bling Bling etc, and i just know he will want me to be using Can Bus systems to let him play with his toys, but i plan on doing so with a redundancy system attached locally somehow. Possibly a simply single pole switch to allow acces to the bus from the relayed unit, and when the system fails computer wise, i can switch the switch and the unit in question will be supplied from the bus directly, removal of the relay (nodes) is possible required too, but I will have to see what develops as the game goes.

I am very concerned with computer comtrolled display switchboards as lightning or even RFI influences could send the whole kit and caboodle haywire....I seem to believe that I have to still somehow allow an alternative manual system into the whole picture too.

I will follow this thread with interest.

[CDK]

I think that using electronic circuit breakers/relays like http://www.e-t-a.com/uk_ssrpcs+M59d7f67440d.html for example can provide all the advantages of a computer controlled power system with the ability to go back to simple circuit breakers if required. ( or just back up each unit with a parallel manual breaker and remove the electronic one in the case of major failure. This gives all the advantages of calders system ( short and open detection , PWM operation , current sensing etc) without the requirments and failure modes of a bus based system

That's no real alternative because you need a set of control wires for each device. That means lots of terminals behind the central console, color coding, cable numbering etc. Adding a device that has not been foreseen means drawing a new cable.
The bus concept has been developed to avoid just that: one power cable, one control wire and an unlimited number of devices.

[goboatingnow]

Dont agree, the whole system can be PCB mounted, with a local CPU to program the switches, The next advantage is that you dont need to place it anywhere near the nav station or console. its actually crasy that companies do that, because you have remote monitoring you dont need physical access to teh board. If fact on most boats theres no need to get to the breakers on a regular basis anyway. Far better to put a couple of switches for common functions ( nav lights etc) on the console. monitoring of the electronic circuit board can be done by a simple CPU and display.

The reason why its an alternative is

(a) point to point traditional wiring, simple to debug and understand
(b) fallback to manual circuit breakers , with (a) above the standard system
(c) you get the benefits of current monitoring, open.short circuit detection, life cycle monitoring etc
(d) allows the circuit break board to be mounted out of sight ( though accessible).

The one power cable method is a very poor fit for small to medium yachts, (a) you have to thread a fairly big cable throughout the boat, (b) any device that draws alot of current will put a lot of noise and voltage drop on teh cable and (c) I suspect that real installations run several such power cable system to provide some redundancy and to isolate high current sources. and this removes some of the advantages anyway.

I have direct experience of distributed power sytems in industrial applications and I think bringing them into yachts is madness

Major failure modes on central power cables are big problems, A direct short takes out all the nodes and also leaves a fault finding mess, particular if the control side of the nodes are powered from the power bus, rather then via the control buss, as all the nodes fail. Then you have the physical access, the nodes are scattered all over the boat in inaccessible places., thirdly while adding a device is theorectically simple, you can bet in the real world the power cable still will not be anyway near where you want it and you'll still have to run extensions. Given that in a 50' foot boat most central panels are within 30 feet of the power consumer the wire runs are small anyway., then forthly you have the issue of people adding on additional nodes outside the total power delivery ability of the cable , resulting in the need to replace the whole power cable

The fact is that bus systems are not the most suitable systems for a environment where (a) the tech level of the user is low (b) uncontrolled expansion may take place and (c) high and low current consumers are mixed.

BTW ligthening damage to these systems is not really a concern, in that generally while ligthening will take on the electronic switching, it also takes out the equipment, hence replacing the switching module may be one thing , finding a new radar or VHf or autopilot is quite another. Ligthening is not a reason to not have distributed swicthing its more a reason not to have anything electrical on board at all.!!

Its interesting to read Calders blog as to what has happened, They had a lot of problems debugging the system that resulted in crasy things happening due to looses connections, they also stripped out delays timers because users didnt understand what was happening ( poor system feedback) etc. I suspect hes reports on this system will be interesting to read. I also understand he has removed the diesel electric propolsuion system as well

The fact is that on large yachts these distributed power systems have been used to power lots of fairly small and mostly identical consumers. ie fire detection, systems monitoring, securtity etc. They have not been used to repalce the whole electricall distribution system as per Calder.

[tanjera]

Please take a look at www.yachtwiring.com

I have personally experienced this system and it is great. Biggest advantage imo is ease of installation, troubleshooting, weight saving and the 'if all else fails' option.

Imo also cheaper (once installed) than conventional system.

Hennie

[apex1]

Go for "Empirbus" Sweden and forget about wiring.

[mark775]

I'm not an electrical engineer and won't pretend. I was sceptical and behind the eightball on wiring, including gages, of my D-9 Volvo. Three sizes of hole saws, a drill motor, a handful of wire ties, four screws, and in 115 minutes it was running. There was one non-critical glitch from using a 12 volt starter and alternator on a system designed for 24 and it was fixed with a coded message in ten minutes another day. Two years later, three lightning storms, not one hiccup. Fuel flow added later, shaft RPM sensor, trolling mode (clutch plate slippage - you want 50 shaft RPM... or 55?), diagnostics, all perfect. I would go with one of these bus systems in a heartbeat and feel that the real advantage comes down the line when you want to add or change something. I have come to trust electrical devices more than mechanical - Simple, clean.

[tanjera]

I am not sure how one can forget about wires with empirbus, unless they came up with something new since I last looked at their system. In fact because of the large number of controllers in one unit you will need more wires than for yachtwiring systems.
Hennie

[Frosty]

I totally and utterly agree that wiring can be simple, but hey who will pay 50 dollars an hour then.

I run small wires to small supplies from bus of bigger wires. it means that I can put in another circuit easily and have a supply without going over load.

I always fit twice as many switches as I need and double the size of conduit. I always needed it.

Do a circuit at a time and write it down as line diagram.

[apex1]

I am not sure how one can forget about wires with empirbus, unless they came up with something new since I last looked at their system. In fact because of the large number of controllers in one unit you will need more wires than for yachtwiring systems.
Hennie

Ja for sure you´re not sure. Wiring in boatbuilders nomenklature is the classical way. A bus system is just installed. And if you need more wires in a bus system (no matter which) you do something completely wrong!

[Stumble]

Earlier this year Professional Boatbuilder did a pretty long spread on the Capi2 system, while I haven't seen it or used a distributed power buss system yet I see a lot of major advantages over traditional wiring systems, and am not willing to dismiss it as an alternative to traditional wiring systems without further investigation.

Advantages:
-Vastly easier installation process than traditional wiring
-Significantly less copper put on the boat
-Easier to trace wiring problems
-Few or no long runs other than the main trunk line, helping to reduce chaff issues, wire routing problems, and simplifying bilge layout
-Much easier to add a new circuit or fixture
-Ability to control groups of points acording to any scheme you can dream up (all lights, all interior lights, all exterior lights, ect) and the ability to quickly change the points in each group
-Wire runs from the trunk to the points can be much smaller since the distance is much less
-Losses due to wiring can be minimized cheaply and overall efficiency gains can be achieved
-Multiple control head can be placed almost anywhere on the boat with minimal wiring (just a data cable run, instead of running load bearing wires)
-Ability to data log each point to determin cycle rates, usage activity, and early warning of failure
-Ability to bypass the computer controllers in the event of a failure (though this would leave multiple circuit breakers scattered throughout the boat instead of one large panel)
-Easier and faster troubleshooting of non-functional points
-Cheaper initial installation
-Cheaper re-wiring job when it becomes necessary
-Remote/internet login and control capability, including the ability of factory technicians to remotly diagnose problems



Disadvantages:
-Like any new technology there is a lack of long term reliability studies
-Must be incorperated from the ground up of a new build or a re-wiring job
-More complexed operation due to advanced features
-Concern over proper shielding
-Lack of qualified technicians who understand the system
-Lack of robust equipment designs to meet varying needs.



Most of this list is from Nigel Calder's article in Professional Boatbuilding june/july 2009. There should be followups to this article which I will be watching closely, but from what I can see now the system seems to be makeing a very good argument that this will become the new way to wire boats in the future.

[apex1]

Stumble
>>>-Like any new technology there is a lack of long term reliability studies<<<

CAN-Bus (Controller Area Network) is the system most of todays installations are based on. That was developed in 1983 by BOSCH Germany and first installed 1987.
It is in use since and installed in the 100 million numbers by so far. Todays Car electronics, Avionics, Med. technique, space exploration, satellites, flight simulators and so on rely on CAN bus. I would say that is truly proven.
NMEA 2000 btw is a further developed sort of CAN.

[tanjera]

Go for "Empirbus" Sweden and forget about wiring.

If you paid attention to my post I said I was not sure how you can forget about wiring with empirbus - it still needs wiring and my point is that it would need a whole lot more than MWS as desribed in www.yachtwiring.com
What is the sense in a distributed control system (on an average size yacht) if one controller switches 32 circuits? You still end up with lots of wires (albeit thinner ones) all over the show!
Please look at the website before you comment again.
Happy wiring
Hennie

[apex1]

If you paid attention to my post I said I was not sure how you can forget about wiring with empirbus - it still needs wiring and my point is that it would need a whole lot more than MWS as desribed in www.yachtwiring.com
What is the sense in a distributed control system (on an average size yacht) if one controller switches 32 circuits? You still end up with lots of wires (albeit thinner ones) all over the show!
Please look at the website before you comment again.
Happy wiring
Hennie

Well I did´nt look at that before today. But it is just another Bus system, there are many good, some not so good and only a few well proven on the market. The best proven by so far is "Empirbus" with the most installations in the commercial and recreational market. And (of extreme importance) best proven software. Look at the Calder article in recent "professional Boatbuilder" issues, he installed "Capi2" (a good system by Victron) and had several problems.

So please forgive that I hammered on your head senseless and without following your link first.

Richard

[Stumble]

Hennie,

I am not sure if I understand your objection, but I think you are objecting to one button controlling 32 circuits as this would require bringing 32 positive and negative wires to the switch. Assuming this is what your objection is to the distributed system you are mistaken in the way a distributed power buss system works.

Instead of having to feed the +/- wire through the boat there is one main trunk pulled bow to stern that every point is attached to. Ideally at the closest physical location between the point and the wire, though in practice there may be some variation due to accessability. So the Nav lights in the bow are making a 3' run to this trunk line, the cabin lights in the stern are making the same 3' run ect. All of the +/- cables from the points connect to a relay and from the relay to the main trunk.

Running right next to the trunk line is a small low voltage data cable, basically a phone line that connects from every relay onboard to the control panel (or panels). When a switch on the control panel is turned on there is a digital data signal sent nown the network to turn on relay numbers X, Y, Z no matter where they are.

The effect of this is that the control panel doesn't need to be actually wired to the power cable, and that the definition of the switches on the control panel can be changed to alter which relays it turns on. So if you wanted a switch that turned on every relay in the boat, that could be wired to just one switch, down to each relay being controlled by a different switch. The control box then only needs the data cable run to it (though it may also be tied to the trunk line for its own power), not the hundreds of wires and supply cables that a traditional instalation would need.

So as an example for a bow thruster that would normally require 00 wire run from the thruster in the bow, to the breaker panel amidship, then to the battery, then back to the bow thruster. on a 50' boat this run is likely to require 60' of cable possibly more. On a distributed system you would have a trunk line of say 000 gague wire running from the batteries forward and dead ending there. Alongside the 000 wire is a phone cord. Where the bow thruster attaches to the trunk you have a relay, then a 0 gage wire from the relay to the thruster, and the phone cable running from the relay to the control box (note that all sizes are made up since I don't know the sizes you would need off hand).

[tanjera]

Hi Richard.
Thanks for looking at the system. I have investigated quite a few of these with the view to installing one myself. I think I can answer the software issue by stating that the owner of MWS is the founder of a very sucsessful software house that, amongst others also designed and maintains all the commodity trading software for the JSE. He is also a qualified Mech & Elec Eng. I have been sailing and motoring on two boats with this system (one has been commisioned three years ago) and am very impressed. It certainly is worth a second look if one is in the market for such a system.

Capt Rubin,
My argument is based on the fact that, having one unit that controls 32 outlets, one is almost back to a centralised system in so far as this controller will invariably be mounted far away from most of the items it controls. Furthermore if something goes haywire, as it surely will, a lot of circuits will be influenced.
The MWS system only has 3 relays per unit and as such can be placed closer to where it is needed. The software is downloaded into each individual unit that then operates autonomously once programmed. If something goes wrong one only has to replace one unit (of 3 relays) which is considerably cheaper than the Empirbus unit. You also have the ability to easily bypass the unit completely with a fused and switched bridge and effectively operate in 'manual' mode without any loss of functionality.
Troubleshooting this system is also made a lot easier by the fact that only three outlets are controlled per unit.
I also like the fact that all the electronics are 'potted' and thus a lot better protected from the vagaries of the boating environment than Empirbus with exposed (relatively) PC boards and connectors.
In terms of cost effective expansion it also has a distinct advantage over Empirbus because it can be done in small increments instead of 32 at a time. In my opinion Empirbus is a system designed for much larger boats and has its place in those applications.
Lastly I agree with Richard that there are quite a few of these around and one should do one's homework before committing to a system.
Regards
Hennie

PS I just recalled an interesting event: The owner of a new 46 ft power cat (four 300hp Suzuki outboards) had some problems during commissioning (builder did not follow installation instructions) and MWS sorted the problem via the internet. They traced the wiring fault and after it was rectified managed to test and control all systems remotely.

[apex1]

Capt Rubin,
[QUOTE]My argument is based on the fact that, having one unit that controls 32 outlets, one is almost back to a centralised system in so far as this controller will invariably be mounted far away from most of the items it controls. Furthermore if something goes haywire, as it surely will, a lot of circuits will be influenced.

I guess you did not understand the slave systems? The module has 8 outputs with automatic fuse functionality. Each channel can deliver up to 8A continously and several channels can be parallelled for large consumers. When something fails it is one of those channels, but that has no influence on the others!

I also like the fact that all the electronics are 'potted' and thus a lot better protected from the vagaries of the boating environment than Empirbus with exposed (relatively) PC boards and connectors.

That has as many pro´s as con´s to encapsulate a unit.

In terms of cost effective expansion it also has a distinct advantage over Empirbus because it can be done in small increments instead of 32 at a time.

8 is the number of increments you physically address, not 32! So your comparison is not exact.

Lastly I agree with Richard that there are quite a few of these around and one should do one's homework before committing to a system.

If so, it is hard to come around Empir bus.

They traced the wiring fault and after it was rectified managed to test and control all systems remotely.

Thats a common feature with almost all systems.

Richard

[apex1]

Capt Rubin,
[QUOTE]My argument is based on the fact that, having one unit that controls 32 outlets, one is almost back to a centralised system in so far as this controller will invariably be mounted far away from most of the items it controls. Furthermore if something goes haywire, as it surely will, a lot of circuits will be influenced.

I guess you did not understand the slave systems? The module has 8 outputs with automatic fuse functionality. Each channel can deliver up to 8A continously and several channels can be parallelled for large consumers. When something fails it is one of those channels, but that has no influence on the others!

I also like the fact that all the electronics are 'potted' and thus a lot better protected from the vagaries of the boating environment than Empirbus with exposed (relatively) PC boards and connectors.

That has as many pro´s as con´s to encapsulate a unit.

In terms of cost effective expansion it also has a distinct advantage over Empirbus because it can be done in small increments instead of 32 at a time.

8 is the number of increments you physically address, not 32! So your comparison is not exact.

Lastly I agree with Richard that there are quite a few of these around and one should do one's homework before committing to a system.

If so, it is hard to come around Empir bus.

They traced the wiring fault and after it was rectified managed to test and control all systems remotely.

Thats a common feature with almost all systems.

Richard

[tanjera]

Richard
If I remember correctly each PC board had 8 channels and each controller takes a max of 4 PC boards.
Where Empir really falls down is when you start comparing costs.
Regards
Hennie

[wardd]

but i like speaking tubes and engine room telegraphs

dont get me wrong i build my own computers to get what i want, but out where its lonely i like the idea of some tape, a roll of wire and a ohm meter, a few extra switches and fuse holders to get me where i want to go

[tanjera]

IMO the MWS (and others) allows you to do exactly that - it is just so much easier to do fault finding and by-pass the fault.
As I said before all you need with MWS is a jumper lead with a suitable inline fuse and switch and Bob's your uncle - problem solved.
The only applications for the computer is the initial downloading (or up grading) of the software, data collection functions and optional switching from the computer. If the smoke comes out of the computer it is no train smash - everything except data collection still works.
Hennie

[apex1]

Richard
If I remember correctly each PC board had 8 channels and each controller takes a max of 4 PC boards.
Where Empir really falls down is when you start comparing costs.
Regards
Hennie

Hennie, I never compare just cost. And luckily my customers do´nt do so either.
When we talk boats we talk trouble, a proven system and a wealthy supplier with a reliable service is more important than a purchase price. There my supplier shines!

Do you mean this:
http://www.empirbus.com/ImageLibrary/1005.gif

when you say "PC boards" ?
Thats the slave module, and that has proven to stand the marine environment.

Richard

[tanjera]

Hi Richard
Yes that is what I was refering to - sorry for the wrong name, but you got the idea. Compare that with a well designed potted system I know which one I will go for!
I wholly agree that one should never make a decision based on cost alone, however I have often ended up buying the more expensive of two items just to discover later that, inspite of a big price differential, it has the same crap inside as the cheaper one!
It is a fallacy to think that one product is better than the next because it is more expensive!
When the customer pays it often is to the advantage of the consultant, advisor, salesman, whatever you want to call him, to sell the more expensive product and they then find that they have to 'invent' all sorts of seemingly good reasons to justify the reccommendation. I am not implying that you are in any way doing that, but I have seen it happen time after time.
Anyway all of the above is not applicable to the normal yachtie that has to figure things out for himself, install it and live with the consequences. To us value for money makes a big difference and when two products of otherwise similar attributes are compared we will always go for the cheapest. In this specific instance I will personally not even consider Empirbus just because of the costs involved for a small system (say 42 circuits).
I cannot let your comment about a 'wealthy' supplier stand without noticing that they needed to bring in Venture capital and dillute their shareholding in order to keep up with development costs!
Lets keep an open non-biased mind and look to see what their new NXT System is like.
Regards
Hennie

[wardd]

usually the quality is in the layout, case and programming not the components as they are usually off the shelf

[pamarine]

I know I'm a late comer to this thread, but Cole Hersee also makes a Bus system (I believe it is called Minibus). Similar systems are found commonly in RVs.

I wil try to read through the thread a bit more and give a more detailed response at a later time.