drewpster
Commander
- Joined
- Oct 17, 2006
- Messages
- 2,059
I just finished some training on multiplexing. I know we deal mainly in older boats here, and that is just how I like it. But the times they are a changin'. I had heard that there are some boat manufacturers that are moving the same direction as many other industries. Multiplex electrical systems are coming! It is a whole new way of thinking in terms of electrical systems that enables all the functions of the system to work through a single pair of wires! Yes, that's right, all the functions, lights, gauges, pumps, engine controls, everything, through two wires. This reduces the amount of wiring significantly throughout the vessel.
It works through the use of computers which control circuits via inputs from a network. Just like your computer at home. I light for instance will turn on with a switch that is connected to a digital network. When the switch is turned on the computer "sees" the signal from that switch and powers the light on. The advantage of this is that the pair of wires that connects the light switch to the light, via the computer, is the same pair of wires that connects the bilge pump switch to its pump. So only a single pair of wires is needed at the control panel. The system also allows all the electrical functions to be programmed into a computer. Lights can be made to fade on and off, flash in an emergency, change to red automatically at night, and just about any other thing a light can be made to do. An indicator on the dash can also let you know if a light bulb is blown or if corrosion is causing too much resistance in a given circuit. And that is just a light!
All the control and indicator panels can be arranged how ever you like. Want to be able to turn on a deck light from the cabin? Easy, just remove the deck light switch from the panel on the deck and plug in to the panel in your cabin. That specific switch controls that specific function. So when the deck light switch is toggled on in the cabin the computer knows to turn the deck lights on. Cool.
It may seem to be overcomplicating things by using this system. However after you understand how the system works you find that it actually simplifies things. Another cool thing about this system is that it can be designed to do just about anything that you can program a computer to do. So the functions and accessories that can be offered using the system is just about infinite. It can also be designed so that upgrades can be easily flashed into the computers if you want a new option later on. Things like LORAN, radar, sonar, fish finders, GPS, Autopilots, can all be integrated into the system. Want your radar to automatically come on, a warning to wake you up, and your cabin lights to come on when a storm is near? Easy, add a panel and a screen to the cabin, plug it in to the network, program the computer and your done! Its all possible.
The first thing I asked in class is what would happen if this simple pair of wires gets damaged, thinking of course the whole system is messed up. The instructor explained that the control computers can have a thousands of contingencies programmed into them. So if communication breaks down in part of the network the computer will activate the contingency. For example in the event a network wire (datalink) gets damaged controlling a deck light the computer will turn on a simple indicator letting the captain know. Or in the event of a lightening strike that takes out a main computer emergency contingencies are automatically put into place controlling necessary systems. Things like engine, steering, bilge pumps, fire abetment, will be in protected circuits or even have manual overrides to insure the boat gets home. The safety in the system comes in the fact that the computers can contain literally thousands of contingencies in the event of failures. Also the most important systems, like the ones I mentioned before, can be designed to have the same safeties that they have always had. Like sailors always say "No matter what hell descends, we have wind and sail".
With the cost of fuel always going up and EPA guidelines getting more strict we are going to find that computers and these types of systems are going to become more prevalent in the future. It may seem complicated but D.I.Y. folks like us are still going to be able to work on these boats. You already have the most important tool you will need right in front of you, your computer. The trick will be changing your way of thinking about electrical systems. Its coming folks! Sooner than you think.
It works through the use of computers which control circuits via inputs from a network. Just like your computer at home. I light for instance will turn on with a switch that is connected to a digital network. When the switch is turned on the computer "sees" the signal from that switch and powers the light on. The advantage of this is that the pair of wires that connects the light switch to the light, via the computer, is the same pair of wires that connects the bilge pump switch to its pump. So only a single pair of wires is needed at the control panel. The system also allows all the electrical functions to be programmed into a computer. Lights can be made to fade on and off, flash in an emergency, change to red automatically at night, and just about any other thing a light can be made to do. An indicator on the dash can also let you know if a light bulb is blown or if corrosion is causing too much resistance in a given circuit. And that is just a light!
All the control and indicator panels can be arranged how ever you like. Want to be able to turn on a deck light from the cabin? Easy, just remove the deck light switch from the panel on the deck and plug in to the panel in your cabin. That specific switch controls that specific function. So when the deck light switch is toggled on in the cabin the computer knows to turn the deck lights on. Cool.
It may seem to be overcomplicating things by using this system. However after you understand how the system works you find that it actually simplifies things. Another cool thing about this system is that it can be designed to do just about anything that you can program a computer to do. So the functions and accessories that can be offered using the system is just about infinite. It can also be designed so that upgrades can be easily flashed into the computers if you want a new option later on. Things like LORAN, radar, sonar, fish finders, GPS, Autopilots, can all be integrated into the system. Want your radar to automatically come on, a warning to wake you up, and your cabin lights to come on when a storm is near? Easy, add a panel and a screen to the cabin, plug it in to the network, program the computer and your done! Its all possible.
The first thing I asked in class is what would happen if this simple pair of wires gets damaged, thinking of course the whole system is messed up. The instructor explained that the control computers can have a thousands of contingencies programmed into them. So if communication breaks down in part of the network the computer will activate the contingency. For example in the event a network wire (datalink) gets damaged controlling a deck light the computer will turn on a simple indicator letting the captain know. Or in the event of a lightening strike that takes out a main computer emergency contingencies are automatically put into place controlling necessary systems. Things like engine, steering, bilge pumps, fire abetment, will be in protected circuits or even have manual overrides to insure the boat gets home. The safety in the system comes in the fact that the computers can contain literally thousands of contingencies in the event of failures. Also the most important systems, like the ones I mentioned before, can be designed to have the same safeties that they have always had. Like sailors always say "No matter what hell descends, we have wind and sail".
With the cost of fuel always going up and EPA guidelines getting more strict we are going to find that computers and these types of systems are going to become more prevalent in the future. It may seem complicated but D.I.Y. folks like us are still going to be able to work on these boats. You already have the most important tool you will need right in front of you, your computer. The trick will be changing your way of thinking about electrical systems. Its coming folks! Sooner than you think.