Tech Talk...
Do we need digital electrics?
Digital is the latest buzzword for electronics, but can it also be successfully applied to
marine electrics to simplify our wiring systems? James Turner investigates.
M
ost of us are reasonably You can even link in a GPRS can do so. Furthermore, you can
familiar with the way (cellphone) unit to keep an eye on set up a reporting system so
the traditional 12V DC things when you aren’t aboard. the boat will tell you if anything
electrical system works on our An analogy to help understand has failed. You can also bring in
boat. In a nutshell, heavy-duty the CAN-bus principle is the an automatic switching system
cables come from the batteries central heating system in your that will turn on the generator if
to a distribution panel, from house. The programmer, boiler, your battery voltage falls below
where two wires go off to every pump and radiators are all a pre-set level. If that all sounds
electrical fitting. Ever had a connected by the hot water too sophisticated, well maybe it
look behind the panel? At best pipe. In a CAN-bus system is, but the basic principle of the
it looks complicated, at worst the batteries, digital DC boat is valid.
it’s a mess. I’ve always found generator, There are two principal times
it difficult carrying out electrical
Above: MasterView
engine and all to consider fitting a digital DC
maintenance, for sure, because Easy display. the electrical system – one is when you are
unless every wire is labelled
Right: MasterShunt
devices are buying a new boat, the other is
– which you rarely see – it takes connected if you are completely re-wiring.
a Sherlock Holmes electrician to along the boat together in Doing it in dribs and drabs
sort out what’s what. – a sort of a DC one Bus. The would be like changing from
Luckily there is now an ring main – then at difference to the driving on the left to driving on
alternative. It’s called CAN-bus convenient points where heating system being the right over a period of time,
technology, which is short for you want to run a number of that you can monitor and rather than all in one go!
Controller Area Network Bus. DC circuits you have a node manage any device from control In order to look at the
Originally developed in the (junction box) to power local units placed anywhere in the components that make up a
1980s by Bosch in Germany for needs. In addition to the big boat. That doesn’t mean that digital DC system I spent some
the commercial vehicle market, cable taking the power to the you have to go to a programmer time with experts at one of the
CAN-bus allows devices to various junction boxes around to turn on a light – of course UK’s major marine electrical
communicate with each other the boat, you also have a single you can still do that at the touch specialists, Mastervolt. It is not
whilst drawing power from a control cable. This enables you of a button – but if you want the only company selling CAN-bus
common source. The principle to monitor, program and control to pre-set the lighting level for for boats, however, so details may
is to run a heavy-duty DC cable every device on your boat. different parts of the boat, you vary with other manufacturers.
7
5
Layout of a typical cruising
8
7
yacht showing a single
4
heavy-duty cable running
6
to each electronically
7
controlled distribution
point, capable of powering
7
10 circuits of 10A each.
1 2 3
3
3 Digital DC Outlet 10x10A
3
4, 5, 7 Switches
6 Digital Input
1 MasterShunt 2 DC Distribution System 8 GPRS Module
60 Sailing Today September 09
ST149
TechTalk_RTG.indd 52 16/7/09 13:11:10
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