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Power over Ethernet (PoE) technology enables ordinary Ethernet network cables to function as power cords. In a PoE-enabled network, direct electrical current (DC) flows over the network cable together with normal Ethernet data traffic. Most PoE devices follow either IEEE standard 802.3af or 802.3at. Power over Ethernet was designed for use with portable and wireless electronic equipment like Wi-Fi access points (APs), webcams, and VoIP phones. PoE allows network devices to be installed in ceilings or wall spaces where electric…
CAN bus in the data frame is sent on the bus, the other CAN controller is through acceptance filtering to determine whether the data on the bus frame ID and this node is consistent, if accord with this node, then the data on the bus were deposited in the bus controller in the corresponding register, or abandon the data, thus able to lighten the load of the bus controller. In other words, the bus data frame ID through after receiving…
As contact with the personnel of optical fiber communication, to the service life of the optical transceiver is concerned about. How long is the service life of it? Industrial-grade fiber optic converter as important optical fiber transmission equipment, in industrial grade fiber optic converter design, the choice of components of nations, it decides the performance of the product, life and cost. Its service life is mainly related to it of light module, the service life of the general in five…
CAN bus terminal resistance, just as its name implies is the resistance of the end of the bus. The resistance is small, but in the CAN bus communication has an important role. The role of terminal resistance There are two: the role of CAN bus terminal resistance A, improve the anti-interference ability, ensure that the bus into the recessive state quickly. Second, improve the quality of the signal. Improve the ability of anti-jamming CAN bus has the "dominant" and "hidden"…
Problem: I am building a CAN bus and I need to know the maximum length of the CAN Bus, or the maximum distance between end Nodes. Additionally, what is the maximum distance that any Node can be from the main CAN bus? Lastly, what values should I use for my termination resistors?Solution: The CAN bus is designed to be setup using a bus network topology. You cannot use a star or a ring topology. The CAN specifications limit how far…
Introduction Over the course of the past fifteen years, building owners, managers and consulting/specifying engineers have become increasingly frustrated by incompatibilities and limited opportunities for the integration of building automation and control systems. Although the sophistication and flexibility of networking and communications technologies in general have been increasing geometrically, controls systems for buildings have carried forward a legacy of proprietary thinking which has impeded the natural migration of many of the benefits of open networking technology into building systems. The…
From the beginning, the CAN network used the high-speed transmission physical layer. It was limited to 1 Mbit/s. This physical layer was originally part of the ISO 11898:1993 standard. After the ISO 11898 document was splitted, it is now specified in ISO 11898-2. Transceivers implementing this standard may be powered with 5 V or 3,3 V. Usage of both kinds in the very same network is possible, but decreases the robustness significantly. On the bus-lines CAN_H(igh) and CAN_L(ow), the transceiver…
Controller Area Network (CAN) electrical systems began to appear in new vehicles in 2003. Since then, more and more vehicles have been equipped with CAN systems, until 2008 when virtually all passenger cars and light trucks sold in the U.S. were CAN-equipped. As a vehicle owner or do-it-yourself mechanic, you need to know how CAN has made the electrical system in late model cars and trucks much more complicated than ever before. CAN allows various modules and systems to share…