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Process Control Network
A Process Control Network (PCN) is a communications network layer that is a part of the Industrial Automation networks in Process Industries. This network is used to transmit instructions and data between control and measurement units and Supervisory Control and Data Acquisition (SCADA) equipment. Industry requirements These networks have, over the years, used many of the technologies and topologies utilised in other network applications. However, Process Control Networks (PCNs) have several special requirements that must be met in order for the solution to be acceptable to the industry. These requirements are, in no particular order: Robustness, Determinacy, Compatibility. Robustness includes requirements such as connection redundancy, reduced sensitivity to Electromagnetic Interference (EMI), and good error checking and correction. Determinacy involves assuring that each device is guaranteed access to the network, and in many cases mechanisms to allow priority information (such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommunications Network
A telecommunications network is a group of nodes interconnected by telecommunications links that are used to exchange messages between the nodes. The links may use a variety of technologies based on the methodologies of circuit switching, message switching, or packet switching, to pass messages and signals. Multiple nodes may cooperate to pass the message from an originating node to the destination node, via multiple network hops. For this routing function, each node in the network is assigned a network address for identification and locating it on the network. The collection of addresses in the network is called the address space of the network. Examples of telecommunications networks include computer networks, the Internet, the public switched telephone network (PSTN), the global Telex network, the aeronautical ACARS network, and the wireless radio networks of cell phone telecommunication providers. Network structure In general, every telecommunications network conceptually ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
De Facto
''De facto'' ( ; , "in fact") describes practices that exist in reality, whether or not they are officially recognized by laws or other formal norms. It is commonly used to refer to what happens in practice, in contrast with ''de jure'' ("by law"), which refers to things that happen according to official law, regardless of whether the practice exists in reality. History In jurisprudence, it mainly means "practiced, but not necessarily defined by law" or "practiced or is valid, but not officially established". Basically, this expression is opposed to the concept of "de jure" (which means "as defined by law") when it comes to law, management or technology (such as standards) in the case of creation, development or application of "without" or "against" instructions, but in accordance with "with practice". When legal situations are discussed, "de jure" means "expressed by law", while "de facto" means action or what is practiced. Similar expressions: "essentially", "unofficial", "in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eurotherm
Eurotherm is a supplier of control and measurement instruments to industrial and process markets. They are part of Watlow, an electricity distribution, automation management and producer of installation components for energy management company. Eurotherm manufacture at a number of locations in Europe and the USA. On October 31, 2022, Eurotherm was bought by Watlow. History The first Eurotherm company, Eurotherm Controls, was formed in 1965 at Worthing, West Sussex to manufacture temperature controllers. In 1970, the directors of the company set up a number of loosely related but independent companies to develop and produce other product lines. Chessell Ltd was created to manufacture data recorders, while Turnbull Control Systems (TCS) was formed to produce process control systems, and Shackleton System Drives (SSD) to produce variable speed electronic drives. All four companies marketed their offerings internationally, and in 1974 they were brought under an international hold ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allen Bradley
Allen-Bradley is the brand-name of a line of factory automation equipment, today owned by Rockwell Automation. The company, with revenues of approximately US $6.4 billion in 2013, manufactures programmable logic controllers ( PLC), human-machine interfaces, sensors, safety components and systems, software, drives and drive systems, contactors, motor control centers, and systems of such products. Rockwell Automation also provides asset-management services including repair and consulting. Rockwell Automation's headquarters is in Milwaukee, Wisconsin. The Allen-Bradley Clock Tower is a Milwaukee landmark featuring the largest four-sided clock in the western hemisphere. History The company was founded in 1903 as the ''Compression Rheostat Company'' by Dr. Stanton Allen and Lynde Bradley with an initial investment of $1,000. In 1910 the firm was renamed ''Allen-Bradley Company''; for close to the next century it provided the bulk of discrete resistors used for electronics and o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Token Passing
On a local area network, token passing is a channel access method where a packet called a ''token'' is passed between nodes to authorize that node to communicate. In contrast to polling access methods, there is no pre-defined "master" node. The most well-known examples are IBM Token Ring and ARCNET, but there were a range of others, including FDDI (Fiber Distributed Data Interface), which was popular in the early to mid 1990s. Token passing schemes degrade deterministically under load, which is a key reason why they were popular for industrial control LANs such as MAP, (Manufacturing Automation Protocol). The advantage over contention based channel access (such as the CSMA/CD of early Ethernet), is that collisions are eliminated, and that the channel bandwidth can be fully utilized without idle time when demand is heavy. The disadvantage is that even when demand is light, a station wishing to transmit must wait for the token, increasing latency. Some types of token passing schemes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Modbus
Modbus is a data communications protocol originally published by Modicon (now Schneider Electric) in 1979 for use with its programmable logic controllers (PLCs). Modbus has become a ''de facto'' standard communication protocol and is now a commonly available means of connecting industrial electronic devices. Modbus is popular in industrial environments because it is openly published and royalty-free. It was developed for industrial applications, is relatively easy to deploy and maintain compared to other standards, and places few restrictions on the format of the data to be transmitted. The Modbus protocol uses character serial communication lines, Ethernet, or the Internet protocol suite as a transport layer. Modbus supports communication to and from multiple devices connected to the same cable or Ethernet network. For example, there can be a device that measures temperature and another device to measure humidity connected to the same cable, both communicating measurements to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open Standard
An open standard is a standard that is openly accessible and usable by anyone. It is also a prerequisite to use open license, non-discrimination and extensibility. Typically, anybody can participate in the development. There is no single definition, and interpretations vary with usage. The terms ''open'' and ''standard'' have a wide range of meanings associated with their usage. There are a number of definitions of open standards which emphasize different aspects of openness, including the openness of the resulting specification, the openness of the drafting process, and the ownership of rights in the standard. The term "standard" is sometimes restricted to technologies approved by formalized committees that are open to participation by all interested parties and operate on a consensus basis. The definitions of the term ''open standard'' used by academics, the European Union, and some of its member governments or parliaments such as Denmark, France, and Spain preclude open standard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standardization
Standardization or standardisation is the process of implementing and developing technical standards based on the consensus of different parties that include firms, users, interest groups, standards organizations and governments. Standardization can help maximize compatibility, interoperability, safety, repeatability, or quality. It can also facilitate a normalization of formerly custom processes. In social sciences, including economics, the idea of ''standardization'' is close to the solution for a coordination problem, a situation in which all parties can realize mutual gains, but only by making mutually consistent decisions. History Early examples Standard weights and measures were developed by the Indus Valley civilization.Iwata, Shigeo (2008), "Weights and Measures in the Indus Valley", ''Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures (2nd edition)'' edited by Helaine Selin, pp. 2254–2255, Springer, . The centralized we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Protocol
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 ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Industrial Automation Networks In Process Industries
Industrial may refer to: Industry * Industrial archaeology, the study of the history of the industry * Industrial engineering, engineering dealing with the optimization of complex industrial processes or systems * Industrial city, a city dominated by one or more industries * Industrial loan company, a financial institution in the United States that lends money, and may be owned by non-financial institutions * Industrial organization, a field that builds on the theory of the firm by examining the structure and boundaries between firms and markets * Industrial Revolution, the development of industry in the 18th and 19th centuries * Industrial society, a society that has undergone industrialization * Industrial technology, a broad field that includes designing, building, optimizing, managing and operating industrial equipment, and predesignated as acceptable for industrial uses, like factories * Industrial video, a video that targets “industry” as its primary audience * In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RS-485
RS-485, also known as TIA-485(-A) or EIA-485, is a standard defining the electrical characteristics of drivers and receivers for use in serial communications systems. Electrical signaling is balanced, and multipoint systems are supported. The standard is jointly published by the Telecommunications Industry Association and Electronic Industries Alliance (TIA/EIA). Digital communications networks implementing the standard can be used effectively over long distances and in electrically noisy environments. Multiple receivers may be connected to such a network in a linear, multidrop bus. These characteristics make RS-485 useful in industrial control systems and similar applications. Overview RS-485 supports inexpensive local networks and multidrop communications links, using the same differential signaling over twisted pair as RS-422. It is generally accepted that RS-485 can be used with data rates up to 10 Mbit/s or, at lower speeds, distances up to . As a rule of thumb, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RS-422
RS-422, also known as TIA/EIA-422, is a technical standard originated by the Electronic Industries Alliance that specifies electrical characteristics of a digital signaling circuit. It was meant to be the foundation of a suite of standards that would replace the older RS-232C standard with standards that offered much higher speed, better immunity from noise, and longer cable lengths. RS-422 systems can transmit data at rates as high as 10 Mbit/s, or may be sent on cables as long as at lower rates. It is closely related to RS-423, which uses the same signaling systems but on a different wiring arrangement. RS-422 specifies differential signaling, with every data line paired with a dedicated return line. It is the voltage difference between these two lines that define the mark and space, rather than, as in RS-232, the difference in voltage between a data line and a local ground. As the ground voltage can differ at either end of the cable, this required RS-232 to use signals with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
