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ETHERNET Powerlink
Ethernet Powerlink is a real-time protocol for standard Ethernet. It is an open protocol managed by the Ethernet POWERLINK Standardization Group (EPSG). It was introduced by Austrian automation company B&R in 2001. This protocol has nothing to do with power distribution via Ethernet cabling or power over Ethernet (PoE), power line communication, or Bang & Olufsen's PowerLink cable. Overview Ethernet Powerlink expands Ethernet with a mixed polling and timeslicing mechanism. This provides: * Guaranteed transfer of time-critical data in very short isochronic cycles with configurable response time * Time-synchronisation of all nodes in the network with very high precision of sub-microseconds * Transmission of less time-critical data in a reserved asynchronous channel Modern implementations reach cycle-times of under 200 µs and a time-precision (jitter) of less than 1 µs. Standardization Powerlink was standardized by the Ethernet Powerlink Standardization Group (EPSG) and f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Real-time Computing
Real-time computing (RTC) is the computer science term for hardware and software systems subject to a "real-time constraint", for example from event to system response. Real-time programs must guarantee response within specified time constraints, often referred to as "deadlines". Ben-Ari, Mordechai; "Principles of Concurrent and Distributed Programming", ch. 16, Prentice Hall, 1990, , page 164 Real-time responses are often understood to be in the order of milliseconds, and sometimes microseconds. A system not specified as operating in real time cannot usually ''guarantee'' a response within any timeframe, although ''typical'' or ''expected'' response times may be given. Real-time processing ''fails'' if not completed within a specified deadline relative to an event; deadlines must always be met, regardless of system load. A real-time system has been described as one which "controls an environment by receiving data, processing them, and returning the results sufficiently quic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Link Layer
The data link layer, or layer 2, is the second layer of the seven-layer OSI model of computer networking. This layer is the protocol layer that transfers data between nodes on a network segment across the physical layer. The data link layer provides the functional and procedural means to transfer data between network entities and may also provide the means to detect and possibly correct errors that can occur in the physical layer. The data link layer is concerned with local delivery of frames between nodes on the same level of the network. Data-link frames, as these protocol data units are called, do not cross the boundaries of a local area network. Inter-network routing and global addressing are higher-layer functions, allowing data-link protocols to focus on local delivery, addressing, and media arbitration. In this way, the data link layer is analogous to a neighborhood traffic cop; it endeavors to arbitrate between parties contending for access to a medium, without co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Safety Integrity Level
Safety integrity level (SIL) is defined as the relative level of risk-reduction provided by a safety function, or to specify a target level of risk reduction. In simple terms, SIL is a measurement of performance required for a safety instrumented function (SIF). The requirements for a given SIL are not consistent among all of the functional safety standards. In the functional safety standards based on the IEC 61508 standard, four SILs are defined, with SIL 4 the most dependable and SIL 1 the least. The applicable SIL is determined based on a number of quantitative factors in combination with qualitative factors such as development process and safety life cycle management. Assignment Assignment of SIL is an exercise in risk analysis where the risk associated with a specific hazard, that is intended to be protected against by a SIF, is calculated without the beneficial risk reduction effect of the SIF. That unmitigated risk is then compared against a tolerable risk target. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IEC 61508
IEC 61508 is an international standard published by the International Electrotechnical Commission consisting of methods on how to apply, design, deploy and maintain automatic protection systems called safety-related systems. It is titled ''Functional Safety of Electrical/Electronic/Programmable Electronic Safety-related Systems'' (E/E/PE, or E/E/PES). IEC 61508 is a basic functional safety standard applicable to all industries. It defines functional safety as: “part of the overall safety relating to the EUC (Equipment Under Control) and the EUC control system which depends on the correct functioning of the E/E/PE safety-related systems, other technology safety-related systems and external risk reduction facilities.” The fundamental concept is that any safety-related system must work correctly or fail in a predictable (safe) way. The standard has two fundamental principles: # An engineering process called the safety life cycle is defined based on best practices in order to dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Functional Safety
Functional safety is the part of the overall safety of a system or piece of equipment that depends on automatic protection operating correctly in response to its inputs or failure in a predictable manner ( fail-safe). The automatic protection system should be designed to properly handle likely human errors, systematic errors, hardware failures and operational/environmental stress. Objective The objective of functional safety is freedom from unacceptable risk of physical injury or of damage to the health of people either directly or indirectly (through damage to property or to the environment) by the proper implementation of one or more automatic protection functions (often called safety functions). A safety system (often called a safety-related system) consists of one or more safety functions. Functional safety is intrinsically end-to-end in scope in that it has to treat the function of a component or subsystem as part of the function of the entire automatic protection func ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epl Cycle-1
EPL may refer to: Computing * Easy Programming Language * Eclipse Public License * Eltron Programming Language, a control language for various computer printers * Ethernet Powerlink, an Ethernet protocol * Early PL/I, a PL/I subset dialect used to write Multics Anatomy * Extensor pollicis longus muscle * External plexiform layer Education * École polytechnique de Louvain, faculty of engineering science at the University of Louvain (UCLouvain), Belgium Libraries * Edmonton Public Library, in Alberta, Canada * Euclid Public Library, in, Ohio, United States * Evanston Public Library, in Illinois, United States * Everett Public Library, in Washington, United States Publications * ''EPL'' (journal), a scientific journal * ''Eesti Päevaleht'', an Estonian newspaper Sports * Egyptian Premier League * English Premier Ice Hockey League * English Premier League * ESL Pro League, a professional ''Counter-Strike: Global Offensive'' league * Everest Premier League, a Nep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epl Cycle-2
EPL may refer to: Computing * Easy Programming Language * Eclipse Public License * Eltron Programming Language, a control language for various computer printers * Ethernet Powerlink, an Ethernet protocol * Early PL/I, a PL/I subset dialect used to write Multics Anatomy * Extensor pollicis longus muscle * External plexiform layer Education * École polytechnique de Louvain, faculty of engineering science at the University of Louvain (UCLouvain), Belgium Libraries * Edmonton Public Library, in Alberta, Canada * Euclid Public Library, in, Ohio, United States * Evanston Public Library, in Illinois, United States * Everett Public Library, in Washington, United States Publications * ''EPL'' (journal), a scientific journal * ''Eesti Päevaleht'', an Estonian newspaper Sports * Egyptian Premier League * English Premier Ice Hockey League * English Premier League * ESL Pro League, a professional ''Counter-Strike: Global Offensive'' league * Everest Premier League, a Nep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethernet Powerlink Cycle
Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 1983 as IEEE 802.3. Ethernet has since been refined to support higher bit rates, a greater number of nodes, and longer link distances, but retains much backward compatibility. Over time, Ethernet has largely replaced competing wired LAN technologies such as Token Ring, FDDI and ARCNET. The original 10BASE5 Ethernet uses coaxial cable as a shared medium, while the newer Ethernet variants use twisted pair and fiber optic links in conjunction with switches. Over the course of its history, Ethernet data transfer rates have been increased from the original to the latest , with rates up to under development. The Ethernet standards include several wiring and signaling variants of the OSI physical layer. Systems communicating over Ethern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carrier Sense Multiple Access
Carrier-sense multiple access (CSMA) is a medium access control (MAC) protocol in which a node verifies the absence of other traffic before transmitting on a shared transmission medium, such as an electrical bus or a band of the electromagnetic spectrum. Under CSMA, a transmitter uses a carrier-sense mechanism to determine whether another transmission is in progress before initiating a transmission. That is, it tries to detect the presence of a carrier signal from another node before attempting to transmit. If a carrier is sensed, the node waits for the transmission in progress to end before initiating its own transmission. Using CSMA, multiple nodes may, in turn, send and receive on the same medium. Transmissions by one node are generally received by all other nodes connected to the medium. Variations on basic CSMA include addition of collision-avoidance (CSMA/CA), collision-detection (CSMA/CD) and collision-resolution techniques. Access modes Variations of CSMA use differen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
8P8C
A modular connector is a type of electrical connector for cords and cables of electronic devices and appliances, such as in computer networking, telecommunication equipment, and audio headsets. Modular connectors were originally developed for use on specific Bell System telephone sets in the 1960s, and similar types found use for simple interconnection of customer-provided telephone subscriber premises equipment to the telephone network. The Federal Communications Commission (FCC) mandated in 1976 an interface registration system, in which they became known as registered jacks. The convenience of prior existence for designers and ease of use led to a proliferation of modular connectors for many other applications. Many applications that originally used bulkier, more expensive connectors have converted to modular connectors. Probably the best-known applications of modular connectors are for telephone and Ethernet. Accordingly, various electronic interface specifications exi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protocol (computing)
A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synchronization of communication and possible error recovery methods. Protocols may be implemented by hardware, software, or a combination of both. Communicating systems use well-defined formats for exchanging various messages. Each message has an exact meaning intended to elicit a response from a range of possible responses pre-determined for that particular situation. The specified behavior is typically independent of how it is to be implemented. Communication protocols have to be agreed upon by the parties involved. To reach an agreement, a protocol may be developed into a technical standard. A programming language describes the same for computations, so there is a close analogy between protocols and programming languages: ''protocols ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
