Understanding Smart Sensors - Nomads.usp

130 Understanding Smart Sensorsreduce the software complexity for distributed control systems in vehicles. Thestandard allows standardized software components to be used across multipleplatforms to reduce development cost and time to market.OSEK was developed to be independent of the communication protocol,so it is compatible with the CAN, J1850, and other automotive protocolsshown in Table 6.2. The combination of application-specific OS, protocol, andsystem hardware, including smart sensors, will be required to improve the efficiency,meet emissions and safety standards, and improve the overall drivingexperience in future vehicles.6.5 Industrial NetworksThe power of a distributed multiplex system is easily demonstrated in factoryautomation. In many cases, users have completed wiring a multiplex systeminstallation with one or two people in a single day, a task that previously took acrew of electrical technicians several days to wire. Also, these installations worksuccessfully the first time, resulting in a considerable cost reduction. Wiring fora multiplex system consists of a twisted pair of wires, power, and ground, whichgreatly simplifies the interconnection process. Once a system strategy is developed,nodes can be added or moved easily without reengineering the system.The nodes can include sensors, as well as valves, motors, and lighting loads.The key is an open standard and plug-and-play capability [7].The industrial market has even more proposed and developing standardsthan the automotive market. Fieldbus is the term for a nonproprietary digitaltwo-way communications standard in the process automation industry. Thefieldbus specification will define the application, data link, and physical layersof the ISO model with some layer-4 services defined. Figure 6.5 illustrates atypical industrial application, with fieldbus as the highest performance leveland a sensor bus at the lowest level [10]. Fieldbus has not been completed, andsemiconductor products are not available to implement the control nodes. Twoprotocols that are attracting a number of industrial users based on available siliconproducts are CAN and LonTalk.6.5.1 Industrial Usage of CANCAN has been adopted for use in industrial applications by manufacturers suchas Allen-Bradley and Honeywell in the DeviceNET system and SDS,respectively. Those communication networks were developed as simpler, lowercost alternatives to fieldbus, which is being developed as an industrial standard.