Digital Switching

How Digital Switching Systems Work

Features that would otherwise be cost prohibitive or technically difficult are now possible.

Power circuit modules are located central to load clusters where the wiring of each circuit is kept to a relatively short length. The number of circuits provided on each power module will vary by design but will typically be in the range of 1 to 16. A pair of relatively heavy cables connect to each of the output modules to source power from the main DC power source.

Input switches and controls are located at functional centres - where they are most convenient for operation. They might incorporate simple rocker style switches, membrane panels or more advanced touch panel electronic displays. While an input circuit might control an individual output, it can also control a group of outputs or some type of mode function.

Analogue inputs provide the capability of interfacing signals such as tank levels, temperature, voltage and current. These are particularly important in that they can be used as logic terms in the control of system functions. For example a pump could be inhibited from operation if the target tank was nearly full.

Interconnecting the entire system is a network that allows the communication of command and status information to and from each module. By employing a common industry standard network such as NMEA 2000, interoperability between system components from many manufacturers is possible.

Those familiar with industrial control applications will see a striking similiarity to PLC (Programmable Logic Control) systems that are ubiquitously employed controlling the machinery of the industrial world. New generation digital switching systems are in effect advanced DC operated PLC systems that are packaged to operate in a harsh marine environment over a wide operating voltage range.

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