The System
The PowerPlex® system by E-T-A Electro enables the control and monitoring of all electronic systems on one robust network to reduce wiring and installation cost. The PowerPlex modules provide overcurrent and short-circuit protection, and will automatically switch off loads if an unsafe condition is detected. The PowerPlex® system is made up of 2 or more modules that communicate with each other uses the Controller Area Network (CAN) bus communication protocol to commutate between different modules.
The loads controlled by the modules - in this case, a light and bilge pump - are normally installed at some place in the vehicle which may not be necessarily close to the input signal. The decentralized control structure of PowerPlex® allows monitoring and switching of the devices anywhere on the vehicle or boat from any chosen installation site. A level sensor monitors the bilge and supplies the analog information on module 1. From there the information is transferred to module 2 via the CAN bus. As soon as the measured analog input value (i.e. the “pumping level”) has exceeded a pre-set limit value, module 2 will send a switch command to the load (i.e. the “bilge pump”) so as to switch on the pump and to reduce the water level of the bilge back to an acceptable level. The status information of the bilge pump will be sent back to module 1 in order to switch on the display “bilge pump running”. In addition, module 2 monitors the position of a light switch – ON or OFF – at one of the digital inputs and sends the switching signal to module 1, which switches the light ON or OFF depending on the switching status.
CAN bus was created by the Society of Automotive Engineers (SAE) out of a need to simplify and reduce the amount of wiring within the automobile industry. A modern car can have over 80 sensors or actuator nodes (i.e. brakes, engine management, indicator lights, dashboard buttons, airbags, etc) that could require over 2.2kms of wiring to interconnect. CAN bus provides a highly reliable and simplified system that allows each sensor to communicate directly with each other and dramatically reducing the amount of wiring and connections required. Today CAN bus is used in all modern road vehicles, marine craft, earthmoving and military vehicles. The system is a low cost, very robust against failure, and electromagnetic interference.