Understanding Smart Sensors - Nomads.usp

306 Understanding Smart Sensors13.6.1 Airplane NetworksFigure 13.7 shows the use of a variation of the IEEE 1451 standard for a jet airplane[15]. The primary difference is the analog output for troubleshooting.Each of a number of buses on the airplane would connect a number of sensorsor actuators to a central DA and/or control system. The connection betweenthe hub and the host computer would be less than 100m and actually may notbe required. A single high-speed cable or fiber-optic link would provide theinterface to the host computer, located remotely from the network. The developmentteam analyzed other available buses and eliminated them for the followingreasons:• They were too slow to support desired data rates.• They required four-wire cable.• They had undesirable features.• There was limited physical distance between points.13.6.2 Automotive Safety NetworkCost-effective simple circuitry for networked control of airbags and other vehiclesafety systems has led to the development of a distributed systems interface(DSI) [16]. The interface is offered as a freely licensable standard. OtherNetworkedsensorNetworkedsensorNetworkedsensorNetworkedsensorHostprocessorNetworkhubNetworkedsensorNetworkedsensorNetworkedsensorBus 1Bus 2Bus 3HostcontrollerBus 16NetworkedsensorNetworkedsensorNetworkedsensorFigure 13.7 Boeing 777 adaptation of IEEE 1451.2. (After: [15].)