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DC-BUS is technology for reliable and economical communication over noisy DC or AC Power lines. The DC-BUS was originally developed by Yamar Electronics Ltd.〔http://www.yamar.com〕 together with the DC-BUS Alliance,〔"The New Automotive 42V PowerNet - Alfons Graf page 192 - objective of the DC-BUS Alliance"〕 for low cost sub-networks in vehicles, using the battery lines for in-vehicle data communication. The DC-BUS converts the digital input data into phase modulated signals, protected against errors generated by noise over the powerline. On the receiving side, the received signal is demodulated into the original digital data.〔The New Automotive 42V PowerNet - Alfons Graf page 191 - The pricnciple of Power Line Communication"〕 Gradually it becomes a popular communication mean 〔"Yamar DC Power-Line Bus Gains Momentum - Hansen Report"〕 in plurality of applications ranging from Aerospace, Automotive, Micro-grid in EV battery, solar energy management and lighting as well as an alternative to RS-232 and RS-485 networks. Common goal for all these applications is reducing wires, saving space, lowering cost and increasing reliability. == Technology == The DC-BUS is a physical layer that allows transmission of data over the powerline and receiving that signal even if attenuated to the noise level of the powerline. Two technologies implement the DC-BUS: Byte oriented and Message oriented. The Signaling technology is byte oriented, allowing transfer of a single UART data byte or more over noisy channel (such as powerline) at bit-rate up to 115.2 kbit/s; Each transmitted byte is protected against errors caused by noisy environment. This method operates on a customer selected channel ranging in the HF band. A unique narrow band signaling modulation, based on combination of phase changes is used to transfer each byte. There is no restriction to the number of bytes, therefore, any UART-based standards such as RS-232, RS-485 and LIN-bus can use the DC-BUS as a physical layer. The received data by all the other nodes on that channel has a fixed latency of 3.5 bits. This simplicity of use allows every customer to design his own protocol or use common industry protocols such as LIN. A master slave upper layer protocol is suitable for network operation. The DCB technology is message oriented, currently operating at speeds up to 1.3Mbit/s. The DCB devices use a selectable narrowband carrier to communicate over the powerline. The DCB gets a message of any length from its host controller and phase modulate it over the power line. The DCB devices have built-in CSMA/CR mechanism for collision detection and arbitration for network operation. The DCB interfaces with its host controller using Standard UART or SPI protocols. The use of low level modulated sine wave instead of digital square wave usually between 0 and 12V generates lower unintentional radiation (EMC).〔(2009 ESA Workshop on Aerospace EMC P1.11 - European Space Agency" )〕 The DC-BUS has a Sleep mechanism to wake up the DC-BUS devices during Sleep mode (low power consumption). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「DC-BUS」の詳細全文を読む スポンサード リンク
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