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Highway Addressable Remote Transducer Protocol
The HART Communication Protocol (Highway Addressable Remote Transducer) is a hybrid analog+digital industrial automation open protocol. Its most notable advantage is that it can communicate over legacy 4–20 mA analog instrumentation current loops, sharing the pair of wires used by the analog-only host systems. HART is widely used in process and instrumentation systems ranging from small automation applications up to highly sophisticated industrial applications. Based on the OSI model, HART resides at Layer 7, the Application Layer. Layers 3–6 are not used. When sent over current loop, 4–20 mA it uses a Bell 202 modem, Bell 202 for layer 1. But it is often converted to RS485 or RS232. According to Emerson,Emerson ''https://web.archive.org/web/20181107104043/https://www.automation.com/automation-news/industry/emerson-proves-advancements-in-eddl-electronic-device-description-language-technology'', rev. 2005-04-14 due to the huge installation base of 4–20 mA systems thr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Current Loop
In electrical signalling an analog current loop is used where a device must be monitored or controlled remotely over a pair of conductors. Only one current level can be present at any time. A major application of current loops is the industry de facto standard 4–20 mA current loop for process control applications, where they are extensively used to carry signals from process instrumentation to proportional–integral–derivative (PID) controllers, supervisory control and data acquisition (SCADA) systems, and programmable logic controllers (PLCs). They are also used to transmit controller outputs to the modulating field devices such as control valves. These loops have the advantages of simplicity and noise immunity, and have a large international user and equipment supplier base. Some 4–20 mA field devices can be powered by the current loop itself, removing the need for separate power supplies, and the "smart" Highway Addressable Remote Transducer (HART) Pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OSI Model
The Open Systems Interconnection (OSI) model is a reference model developed by the International Organization for Standardization (ISO) that "provides a common basis for the coordination of standards development for the purpose of systems interconnection." In the OSI reference model, the components of a communication system are distinguished in seven abstraction layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application. The model describes communications from the physical implementation of transmitting bits across a transmission medium to the highest-level representation of data of a distributed application. Each layer has well-defined functions and semantics and serves a class of functionality to the layer above it and is served by the layer below it. Established, well-known communication protocols are decomposed in software development into the model's hierarchy of function calls. The Internet protocol suite as defined in and is a model of net ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bell 202 Modem
The Bell 202 modem was an early (1976) modem standard developed by the Bell System. It specifies audio frequency-shift keying (AFSK) to encode and transfer data at a rate of 1200 bits per second (bit/s), half-duplex. It has separate sets of circuits for 1200 bit/s and 300 bit/s rates. These signalling protocols, also used in third-party modems, are referred to generically as ''Bell 202 modulation'', and any device employing it as ''Bell-202-compatible''. * Bell 202 AFSK uses a 1200 Hz tone for ''mark'' (typically a binary ''1'') and 2200 Hz for ''space'' (typically a binary ''0''). In North America, Bell 202 AFSK modulation is used to transmit Caller ID information over POTS lines in the public telephone network. It is also employed in some commercial settings. In addition, Bell 202 is the basis for the most commonly used physical layer for the HART Communication Protocol - a communication protocol widely used in the process industries. Surplus Bell 202 modems ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rosemount Inc
Rosemount may refer to: Place names Australia * Rosemount, Queensland Canada * Rural Municipality of Rosemount No. 378, Saskatchewan Ireland * Rosemount, County Westmeath, an area in the Southwest of Westmeath United Kingdom * Rosemount, Aberdeen, an area of the Scottish city of Aberdeen * Rosemount, County Down, a townland in County Down, Northern Ireland * Rosemount, Derry, an area of Derry, Northern Ireland * Rosemount, Perth and Kinross, a location in Scotland United States * Rosemount (Forkland, Alabama), a plantation in Forkland, Alabama, listed on the NRHP in Alabama * Rosemount Museum, a historic house museum in Pueblo, Colorado, listed on the NRHP * Rosemount, Minnesota * Rosemount, Ohio Other uses * Rosemount (wine), an Australian brandname owned by Treasury Wine Estates * Rosemount Inc., a manufacturer of industrial process measurement devices, and Rosemount Engineering, the original name of the company * Rosemount International School, Singapore * Rosem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open Protocol
An open standard is a standard that is openly accessible and usable by anyone. It is also a common prerequisite that open standards use an open license that provides for extensibility. Typically, anybody can participate in their development due to their inherently open nature. There is no single definition, and interpretations vary with usage. Examples of open standards include the GSM, 4G, and 5G standards that allow most modern mobile phones to work world-wide. Definitions 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smart Current Loop Positioner
''SMart'' was a British CBBC television programme based on art, which began in 1994 and ended in 2009. The programme was recorded at BBC Television Centre in London. Previously it had been recorded in Studio A at Pebble Mill Studios in Birmingham. The format is similar to the Tony Hart programmes '' Take Hart'' and '' Hartbeat''. The show was revamped into an hour-long show in 2007; from 1994 to 2006 it was previously a 25-minute show. From 1994 to 2005, the show also featured Morph, originally from ''Take Hart''. The series run featured 199 episodes, last airing on 11 August 2011. Production The BBC noticed the success of '' Art Attack'' with Neil Buchanan for CITV which started in 1990 and decided to create their own art show that was accessible to children similar to ''Art Attack''. The original theme tune was composed by Kjartan Poskitt, famous for the '' Murderous Maths'' series of books. From 2003, a different tune was used, written by Steve Brown (known as the fictiona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Current Loop
In electrical signalling an analog current loop is used where a device must be monitored or controlled remotely over a pair of conductors. Only one current level can be present at any time. A major application of current loops is the industry de facto standard 4–20 mA current loop for process control applications, where they are extensively used to carry signals from process instrumentation to proportional–integral–derivative (PID) controllers, supervisory control and data acquisition (SCADA) systems, and programmable logic controllers (PLCs). They are also used to transmit controller outputs to the modulating field devices such as control valves. These loops have the advantages of simplicity and noise immunity, and have a large international user and equipment supplier base. Some 4–20 mA field devices can be powered by the current loop itself, removing the need for separate power supplies, and the "smart" Highway Addressable Remote Transducer (HART) Pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polling (computer Science)
Polling, or interrogation, refers to actively sampling the status of an external device by a client program as a synchronous activity. Polling is most often used in terms of input/output (), and is also referred to as polled or software-driven . A good example of hardware implementation is a watchdog timer. Description Polling is the process where the computer or controlling device waits for an external device to check for its readiness or state, often with low-level hardware. For example, when a printer is connected via a parallel port, the computer waits until the printer has received the next character. These processes can be as minute as only reading one bit. This is sometimes used synonymously with ' busy-wait' polling. In this situation, when an operation is required, the computer does nothing other than check the status of the device until it is ready, at which point the device is accessed. In other words, the computer waits until the device is ready. Polling also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Current Loop Interface
For serial communications, a current loop is a communication interface that uses current instead of voltage for signaling. Current loops can be used over moderately long distances (tens of kilometres), and can be interfaced with optically isolated links. There are a variety of such systems, but one based on a 20 mA current level was used by the Teletype Model 33 and was particularly common on minicomputers and early microcomputer which used these as computer terminals. As a result, most computer terminals also supported this standard into the 1980s. History Long before the RS-232 standard, current loops were used to send digital data in serial form for teleprinters. More than two teleprinters could be connected on a single circuit allowing a simple form of networking.E. A. Parr, ''Industrial Control Handbook'', Industrial Press Inc., 1998, , page 648 Older teleprinters used a 60 mA current loop. Later machines, such as the Teletype Model 33, operated on a lower 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Checksum
A checksum is a small-sized block of data derived from another block of digital data for the purpose of detecting errors that may have been introduced during its transmission or storage. By themselves, checksums are often used to verify data integrity but are not relied upon to verify data authenticity. The procedure which generates this checksum is called a checksum function or checksum algorithm. Depending on its design goals, a good checksum algorithm usually outputs a significantly different value, even for small changes made to the input. This is especially true of cryptographic hash functions, which may be used to detect many data corruption errors and verify overall data integrity; if the computed checksum for the current data input matches the stored value of a previously computed checksum, there is a very high probability the data has not been accidentally altered or corrupted. Checksum functions are related to hash functions, fingerprints, randomization functio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Protocols
A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any 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 predetermined 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 are to communicat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Industrial Computing
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 **Second Industrial Revolution * 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
