JAOMAD Glossary R:
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Intro
R—Symbol of ANSI thermocouple type for Platinum 13% Rhodium vs. Platinum; Symbol for Rankine, an absolute temperature scale based upon Fahrenheit scale with 0°F = 459.67°R; also: means "Radiation" when used in first alpha character position of ISA instrument function tag, means "Record" or "Print" in succeeding position [see ANSI/ISA S5.1-1984 (R1992)]; also: means Range of sample values in SPC.
R&D—Research & Development.
RAE—Real-time Application Environment.
Raceway—Enclosed channel designed expressly for holding wire, cables or bus bars; typically one side is removable for access in laying cable; in contrast with conduit, which is open only at the ends of the run.
RAD—Rapid Application Development tools; computer software “toolkit” to allow creation of powerful, easy to use, end user applications, usually through drag-and-drop methods into different databases; examples include Microsoft® VisualBasic, Sybase® PowerBuilder, and Oracle® Developer2000.
RADAR—RAdio Detection And Ranging; works by sending out radio waves and listening for their reflections, a principle used in several sensor designs particularly for motion, flow, and level detectors.
Radial Arm Saw—Large stationary power saw primarily used by most shops to scare neophytes into choosing another line of work. J
Radial Clearance—See Clearance, Radial.
Radio Buttons—Selectors within operator (or configuration) screen view usually for responding to choice of options; form is small empty circle in which a dot appears when selected.
Radio Frequency Interference (RFI)—Term used interchangeably with EMI. EMI is a later definition that includes entire electromagnetic spectrum, whereas RFI is more restricted to radio frequency band, generally considered to be between 10k and 10G Hz; unwanted "noise" created by field producing devices such as "walkie-talkies" and citizen band (CB) radio transmission equipment effecting quality of signals passing through some data transmission medium
RADIUS—Access control software protocol that uses challenge/response method to authenticate a user in protected communication system.
Ragged Left—In screen text and typesetting, type that is justified on right margin and ragged on left.
Ragged Right—In screen text and typesetting, type that is justified on left margin and ragged on right.
RAID—Redundant Array of Independent Disks; provide large amount of memory by “stacking” numbers of inexpensive hard disk drives; also: have seen this defined as Redundant Array of Inexpensive Disks.
RAID Array Level 1—Redundant Array of Independent Disks; disk mirroring, actually duplication of partition; some may refer to this as partition redundancy; requires minimum of two hard disks, but mirroring results in 50% loss of available disk capacity (using two equally sized partitions to store same information); really used for reliability rather than performance.
RAID Array Level 2—Redundant Array of Independent Disks; in video development, with Raid Level 2, sustained data throughput is enhanced by allowing drives to take turns reading or writing high speed stream of information, ideal for motion JEPG configurations.
RAID Array Level 5—Redundant Array of Independent Disks; disk striping with parity distributed across multiple drives; minimum of three drives required to create level 5 partition, if single disk in set fails, enough information is stored to allow data to be completely reconstructed on replacement drive; total capacity of disks is not available for data storage, nut part is used to calculate and store parity information; although slower than mirroring for disk writing operations, offers much better reading performance.
RAMDAC—Random Access Memory Digital-to-Analog Converter; single chip on video adapter cards to convert digitally encoded images into analog signals that can be displayed by a monitor; actually consists of four different components - SRAM to store color map and three digital-to-analog converters (DACs), one for each of monitor's red, green, and blue electron guns.
RALU—Register and Arithmetic/Logic Unit.
RAM—Random Access Memory; storage device into which data can be entered (written) and read while system is operational; memory is volatile and data will be lost if power is removed; see DRAM, MRAM, SRAM.
Range—In instrumentation, those values over which sensor or transducer is intended to measure, signal is intended to be transmitted/recieved, or equipment is intended to operate; usually specified by its upper and lower limits; see Operating, Compensated.
Range Resistors―Precision resistors for 4-20mA transmitters that are typically 250 ohms ±0.25 ohms with a temperature coefficient of not more than 0.01%/8C, used to convert 4-20mA signals to 1-5Vdc signals; also called Dropping Resistors.
Rangeability— Relationship between range and minimum quantity that can be measured; also: ratio of maximum flow rate to minimum flow rate of meter or valve; also: installed rangeability is ratio of maximum to minimum flow, within which limits deviation from desired installed flow characteristic does not exceed some stated limits; also: inherent rangeability is ratio of largest flow coefficient (Cv) to smallest flow coefficient within which deviation from specified inherent flow characteristic does not exceed stated limits, such as in a valve alone.
Rapid Economic Justification (REJ)—Study that quantifies impact of executives’ technology decisions, providing plant executives with data on deployment costs and projected business, technical, and financial benefits; key factors include technical architecture, critical business success factors, risks, deployment and configuration costs, hardware upgrades or replacements, application compatibility testing and migration, project management, documentation, and training for information services staff.
Rapid Prototyping—Using ultraviolet cured photopolymers to build up three-dimensional solid objects in layers from a 3-D CAD database, to give designer ability to have accurate physical representation of a part in a matter of hours or days without expensive tooling.
Rapid Spanning Tree Protocol (RSTP)—Network protocol to provide redundant paths in local networks, disable, or if necessary (failure of a connection) to restore connections and addresses of every device in the system (creating a new topology); an evolution of Spanning Tree Protocol (STP) and compensates its main criticisms; upon failure of components or devices in RSTP, a new topology is automatically recalculated immediately removing the failed paths, whereas in STP the previous paths continue to exist until the calculation has completely finished the new topology (much slower process). RSTP changeover to the new topology is therefore very fast; it is in the standard IEEE 802.1D-2004 definitions.
Rapid Thermal Process—Process in which biomass such as wood chips or straw is rapidly heated at ambient pressure to generate high yields of a light, pourable liquid bio-oil, which in turn can be burned for energy in industrial boilers and furnaces.
Raster—In display on a video screen, grid pattern of vertical and horizontal divisions outlining all the small elements of which picture is composed.
Raster Imaging—Video image which stutters slightly when depicting motion; see Full-motion Imaging.
Raster Image Processor (RIP)—In computer imaging, hardware/software process that results in electronic bit map of an image which indicates every spot position on a page in preparation for actual printout; are designed to rasterize specific type of data, such as PostScript or vector graphics images, as well as different kinds of raster data.
RAT—Remote Administration Tool; see definition.
Rate Action—Another term for Derivative control action in process control; the proportioning of output to rate of change of input.
Rate of Rise—Time for signal to move from 10% to 90% of maximum signal value; see Rise Time.
Rate of Fall—Time for signal to move from 90% to 10% of maximum signal value; see Fall Time.
Ratio Controller—Controller that maintains predetermined ratio between two or more variables; can be one that maintains magnitude of controlled variable at some fixed ratio to another variable.
Ratio Meter—Measuring instrument whose pointer deflection is proportional to ratio of currents passing through two coils; measures quotient of two electrical qualities.
Rayleigh Scattering—Scattering of light in fiber optic cable that results from small inhomogeneities in material density or composition.
RB—Resource Block; see definition.
RBE—Report By Exception; method to rapidly report information in large process control communication systems by only communicating data, which change, or indicates anomalies, rather than report everything.
RCF—Relative Centrifugal Force = (11.18 x 10-6) (rotating radius in cm) (rotating speed in rpm).
RCM—Reliability Centered Maintenance; process systematically identifies all of plant & process asset's functions and functional failures, and identifies all of its reasonably likely failure modes (or failure causes), proceeds to identify effects of these likely failure modes, identify in what way those effects matter, selects most appropriate asset management policy; considers all asset management options: on-condition task, scheduled restoration task, scheduled discard task, failure-finding task, and one-time change (to hardware design, operating procedures, personnel training, or other aspects of the asset outside the strict world of maintenance).
RCRA—Resource Conservation & Recovery Act; U.S. federal law passed in 1976 to regulate management and disposal of solid and hazardous wastes.
RDA—Remote Database Access; ISO draft std that incorporates SQL.
RDBMS—Relational Data Base Management System; see definition.
RDF—Resource Description Framework; see definition.
RDF Site Summary (RSS)—See Rich Site Summary.
RDRAM—Rambus Dynamic Random Access Memory; developed by Rambus, Inc. in conjunction with Intel Corp. and other Rambus semiconductor partners for high performance memory interface in multimedia packages, but migrated to main memory in process control system workstations.
Real Time—Current time or moment when process or event occurs; computer operating mode that allows immediate interaction with data as it is created, as in process control system or computer aided design system; in process control, necessary calculations and control functions are performed as inputs occur, rather than preprocessing or predetermining control response.
Real Time Kernel—In PC Controllers, this makes Windows NT a service to real-time activities and acts as lowest interrupt available to the real-time engine; all control and real-time functions have the first opportunity to complete before an NT application can become active.
Real Time Operating System (RTOS)—Software of computer that controls execution of application programs, which allow immediate interaction with data as it is created, as in process control system.
Real Time Optimization (RTO)— In process control, this package sits above the regulatory strategy and any adaptive or predictive control packages, to perform steady state optimization at the plant level; uses plant models, business requirements, plant-wide operating conditions, forecast and scheduling information to predict optimal products to make in a plant, when to make them and what is the best operating conditions to maximize profitability; most real time plant optimization at the turn of the millennium has been applied to continuous plants making a few, high volume products (e.g.: refineries, petrochemicals, ammonia).
Real Time Process Management—Results of integrating real-time process data from DCSs with business management information systems (MIS) so that activities and events report and respond as they happen.
Real-time Process Optimization & Training (RPO)—Includes advanced process control, on-line optimization, and dynamic simulation for training.
Real Time SubSystem (RTSS) —In computer software, that part of the operating system that runs all of its threads before any NT threads.
Record—Collection of related information that is treated as a single unit.
Recovery Time—Length of time, which it takes a device to return to normal tolerances after an upset.
REDOX—REDuction-OXidation potential; process industries term for ORP.
Redundancy—Duplicate equipment or transmission path to prevent any failure of a function (vs. Fault Tolerant).
Redundancy Check—In digital transmission, technique of error detection involving transmission of additional data related to the basic data so that receiving terminal, by comparing the two sets of data, can determine probability if error has occurred in transmission.
Reference Junction—Cold junction in thermocouple circuit, which is held at stable known temperature.
Reference Manual—Object that raises computer monitor to eye level, also used to compensate for that short table leg. J
Refractive Index—Ratio of phase velocity of light in vacuum to that in specified medium.
Regenerative Repeater—Repeater designed for digital transmission that both amplifies and reshapes signal.
Register—Storage device with specific capacity, such as a bit, byte, or word; also: in screen display development and printing, fitting of two or more images in exact alignment with each other.
REJ—Rapid Economic Justification; see definition.
Relational Data Base Management System—Computing systems which allow data access based upon relationships set up among several database files; powerful because it requires few assumptions about how data is related or how it will be extracted from the database, so same database can be viewed in many different ways; Structured Query Language (SQL) has been accepted as “de facto standard” to retrieve information from these table-structured associations; compare Flat File Database, Multidimensional Database.
Relative Accuracy—In instrumentation, measure in least significant bit of accuracy of analog to digital conversion, including all non-linearity and quantization errors.
Relative Flowrate Error—Margin of variation between design flowrate and actual flowrate for a given valve opening.
Relay—Electromechanical device that completes or interrupts electrical circuit by physically moving conductive contacts; solid state switching device which performs same function with no moving parts; any electric, pneumatic, or hydraulic switch that is actuated by a signal; allowing small signal to control much larger one, or to operate additional devices in the same or different circuits; in instrumentation, device whose function is to pass on information in unchanged form or in some modified form, the term often used to mean "Computing Device," in this case the latter is the preferred term.
RELMS—Residential Energy and Load Management System of EPRI.
REM—Registered Environmental Manager (U.S.); certified category listed by National Registry of Environmental Professionals (NREP).
Remote—Not hard wired; usually communicating long distance over microwave, telephone, satellite, etc.; often referring to devices quite separated from main portions of system, such as an RTU.
Remote Administration Tool (RAT)—Used to remotely connect and manage a single or multiple computers with a variety of software tools; Its primary function is for one computer operator to gain access to remote PCs; one computer will run the "client" software application, while the other computer(s) operate as the "host(s)".
Remote Diagnosis—Diagnosis at a distance; usually by Extranet, Intranet or Internet.
Remote I/O—Input or output electronics for process control system that is mounted relatively near actual process, typically in harsher environment than a control room, or location of controllers themselves.
Remote Procedure Call (RPC)—In computing equipment to pass processing work from busy systems to less busy systems (often “remote”), or from systems that lack specific functionality to systems that have that functionality.
Remote Termination Unit—Sometimes called Remote Telemetry Unit; cabinet for field connections to transmitted data, and do remote discrete switching over some (often extreme) distance from the actual processing of control and operations; usually associated with SCADA systems for power transmission & distribution, water, oil & gas pipelines; recent usage includes “smart” RTUs (with microprocessors) for local computing in field with communications back to plant via control system I/O channels or digital techniques; RTUs must be capable of operating unattended for periods of time with no communication with the balance of system.
Rep—Independent Representative, of a company or product line.
REPA—Registered Environmental Property Assessor (U.S.); certified category listed by National Registry of Environmental Professionals (NREP).
Repeat Accuracy—Ability for controller, timer, etc. to repeat results within tolerance limits.
Repeatability—Ability of sensor, transducer, meter, or other equipment (or system) to duplicate same output, value, or action when same stimulus is applied to it consecutively, under same conditions, and in same direction (does not include hysterisis) over specified number of cycles, or specified time duration; usually expressed in percent as maximum difference between measurements; compare with Reproducibility.
Repeater—In digital transmission, equipment that receives a pulse train, amplifies it, retimes it, and then reconstructs signal for retransmission to extend distance between stations; in fiber optics, a device that decodes a low power light signal, converts it to electrical energy, and then retransmits it via LED or laser light source; also: a regenerative repeater; also: in Ethernet networks, repeaters link multiple segments in either bus or star topology; fully IEEE 802.3 compliant repeaters regenerate and retime signal of each packet of information and automatically partition and isolate faulty segments when collisions occur on the same network; repeaters, hubs, and concentrators all technically perform same basic function.
Repository for Industrial Security Incidents (RISI)—World’s largest database of security incidents in control and SCADA systems. (www.securityincidents.org)
Report by Exception—Method to rapidly report information in large process control communication systems by only communicating data, which change, or indicates anomalies, rather than report everything.
Reproducibility—In process instrumentation, closeness of agreement among repeated measurements of output for same value of input made under same operating conditions over a period of time, approaching from both directions; expressed in percent of span for specified time period and hysterisis, dead band, drift and repeatability; see Repeatability.
Reserved Word—Word that has a defined function in the language, and cannot be used as a variable name.
Reset Action—Another term for Integral control action in process control; also: with timers, the time to move from time-out state to reset state.
Resistance Temperature Detector—Temperature measuring device in which resistance of sensing element is an accurately known function of temperature.
Resistance Thermometer Bulb—Temperature measuring device in which expansion and contraction of a fill, such as mercury and certain other gasses and liquids, is calibrated to reflect change in temperature.
Resolution—In control, smallest measurable magnitude of output step changes as stimulus is continuously varied over specific range; usually expressed in percent of full scale output; also: in digital computing, significance of least significant bit representing a value, see also Accuracy and Precision; when converting from analog to digital, resolution is usually limited by number of bits used to quantify the signal (a 12-bit A/D can resolve to one part in 4096 or 212); also: in video, the number of pixels used in a screen display.
Resonant Frequency—Measurand frequency at which system or device, such as transducer, responds with maximum amplitude.
Resource Block (RB)—In FOUNDATION Fieldbus technology, describes characteristics of fieldbus device such as device name, manufacturer and serial number; only one Resource Block (RB) in a device.
Resource Description Framework (RDF)—Family of World Wide Web Consortium (W3C) specifications originally designed for designing content of Web pages in XML but which has come to be used as a general method of modeling information, through a variety of syntax formats; provides common tags for describing data and graphic elements which allows structure for meta-data; example: using RDF descriptor for zip code would let systems exchange zip code data that use different names for that data element such as "ZIP" and "ZIPCODE."
Response Surface Methodology—Statistical method in which data from suitably designed experiments is used to construct polynomial response models, the coefficients of which are determined by regression techniques.
Response Time—Length of time required for output of system or device to change to specified percentage of its final value as result of step change of input; also: in computers, lapsed time between generation of last character of message at a terminal and receipt of first character of reply, it includes terminal delay and network delay; also: in power lines, how fast surge protector responds to block power surge, also known as "clamp time."
Responsively—In fiber optics, ratio of photodetector's electrical output to its optical input in Amperes/Watt.
Retinex Algorithms—Video input image defining algorithms that automatically compare images which combine dynamic range compression and color consistency with correct lightness and color rendition; overcomes discrepancy between what natural eye sees and image camera acquires when lighting or illumination conditions change (as happens with retina of eyeball).
Retransmissive Star—Star coupler; in fiber optic transmission, passive component that permits light signal on input fiber to be retransmitted on multiple output fibers; formed by heating together one end of a bundle of fibers to near melting point, the other end is distributed to other locations in fiber optic LANs.
Retrofit—Backwards integration of advanced capability into device or program not originally intended for that purpose.
Reuse—In object oriented software, implementation of methods from one or mere objects, but not necessarily as a subclass; if pieces of two objects are combined, the new object inherits all of their class(es) attributes and methods; other mechanisms of reuse include aggregation and containment, which do not inherit functionality from other objects.
Reusability—In Object Oriented Programming (OOP), objects that can be reused.
Reverse Auction—Internet auctioning process (auction) primarily used for e-procurement of investment goods or large contract volumes, where the buyers lays out his technical requirements and asks the sellers for bids. The actual auctioning process is normally prepared by a detailed analysis of technical specifications submitted by bidding companies in advance.
Reverse Channel—Channel used for transmission of supervisory or error control signals; direction of flow of these signals is in direction opposite to that in which information is being transferred.
Reverse Compatible—Designs, which provide compatibility with earlier versions.
Reverse Polarity Protection—Circuitry, usually diode, which prevents current from flowing into some device in case of accidental mis-wiring of plus (+) or minus (-) terminals, preventing damage to the unit.
Reverse Start Timer—Starts timing when power is removed from start circuit, but does not reset during power loss, but retains cycle progress and continues cycle when power is restored; in electromechanical versions, clutch action is reversed so it is normally closed with absence of input control power, and clutch resets timer upon application of power.
Reverse Type—In typographical composition of screen displays and printing, light typeface on dark background.
Reynolds Number—Ratio of inertial and viscous forces in a fluid; within cylindrical channel like a pipe, equals fluid density times velocity times inside pipe diameter divided by viscosity; other shapes will differ.
RF—Raised Face; also: Radio Frequency (above 104 Hz and below 3x1012 Hz).
RFC—Remote Function Call; in remote computing, generally to trigger release of data, translation of information, etc.; also Request For Comment, as when polling group of people creating standards.
RFC1006—Specification for sending OSI application layer messages (such as MMS) via TCP/IP.
RFDC—Radio Frequency Data Communication; in manufacturing industries, refers to data terminals with built-in scanner to read bar code symbols, modem, input/output interface, radio, and digital board usually for inventory management.
RFI—Radio Frequency Interference; see definition.
RFID, RF/ID—Radio Frequency IDentification; reader/transmitter protocol, usually proprietary with each vendor, along with reader (antenna & decoder), a tag (transponder), and a host controller usually for factory automation, transportation, and personal access applications where barcode labels are too vulnerable.
RFP—Request For Proposal.
RFQ—Request For Quote.
RFS—Remote File Sharing developed by AT&T®.
RFT—Right First Time; mathematical inverse of Not Right First Time (NRFT), an error rate measuring technique of effectiveness for QA/QC.
RGA—Relative Gain Array; method of controlling processes with interactions of multiple variables.
RGB—Red/Green/Blue; analog NTSC video signal between commercial monitors and equipment such as VCRs and some computers; also: a model or color space to convey color information; combining differing amounts of these additive primary colors produce all the colors in the color space; used by most monitors and most desktop scanners, it works by starting with no light (black) and then adding quantities of red, green, or blue light (maximum of all three produce white); compare with CMYK; see Additive Primaries.
RH—Relative Humidity; amount of water vapor present, measured in percent of (absolute humidity) / (absolute humidity in saturation) at the same temperature.
Rheometer—Laboratory device used to measure the way in which a liquid, suspension or slurry flows in response to applied forces, used for those fluids which cannot be defined by a single value of viscosity and therefore require more parameters to be set and measured than is the case for a viscometer.
Rheostat—A variable resistor.
RI—Ring Indicator; indicates phone line "ring" between two computer telephone modems.
Ribbon Cable—Flat cable in which conductors are side-by-sider.
Rich Client—In client/server architecture, client that performs bulk of data processing operations; data itself is stored on server; usually refers to software, it can also apply to network computer that has relatively strong processing abilities; also called Thick Client, Fat Client; see thin client for contrast.
Rich Site Summary (RSS) or RDF Site Summary (RSS)—XML-based format for headline syndication, in which headlines and links to the actual content are made available to other Web sites. After the publishing site creates an RSS file of its content, other Web sites may use the headline feed, and the content can be read with a standard Web browser or by specialized RSS viewers.
Ring Expansion—In digital communication, media access protocol method whereby station in network monitors message stream of all messages passing through it until it detects a lull in traffic, whereupon it inserts its own message while buffering and later retransmitting any additional incoming messages; named because method "expands" ring of data by one message until original message or acknowledgment by receiving station returns back to sender; also called Carrier Insertion.
Ring Network—Network topology in which each node is connected to two adjacent nodes, the entire network forming a closed ring; communication between any two points must include the intermediate points.
RIO—Remote Input/Output; direct wired or proprietary link from process sensors to controller, as compared with a digital system such as “standard” fieldbus.
RIP—Raster Image Processor; see definition; also: Routing Information Protocol; see definition.
Ripple—Periodic and random deviation of output voltage of a power supply; this may be composed of line-related components and noise induced from other sources; specified in terms of RMS value or peak-to-peak over bandwidth.
RISC—Reduced Instruction Set Computing; by IBM® & Apple®, internal computing architecture with less processor instructions so that most functions can be performed in a single cycle, improving efficiency and speed; compare with CISC.
Rise Time—Time required for leading edge of a pulse to rise from 10% to 90% of its amplitude; time required for a component to produce such a result such as for output voltage to rise from state of low voltage to high voltage level, once a level change has started.
RISI—Repository for Industrial Security Incidents; world’s largest database of security incidents in control and SCADA systems. (www.securityincidents.org)R/J—Reference Junction, the "cold" junction of a thermocouple.
Risk Management—An analysis of the risk sensitivities residing within each project, as the basis for determining confidence levels across the portfolio; includes integration of cost and schedule risk management with techniques for determining contingency and risk response plans, enable organizations to gain an objective view of project uncertainties and to develop a ‘risk adjusted schedule.’
R/J—Reference Junction, the "cold" junction of a thermocouple.
RJC—Reference Junction Compensation.
RLE—Run Length Encoding; data compression technique which saves data by a single count byte & a repeat byte rather than use memory to save a repetitive group of bytes [example: 777777 becomes "count of 6 with value of 7 (two bytes)].
RLL—Relay Ladder Logic; see Ladder Logic.
RMA—Reliability Maintainability and Availability.
RMI—Radio Frequency Interference; to electrical and digital signals.
RMM—Read Mostly Memory; also: Read Mostly Mode.
RMP—Rick Management Program.
RMS—Root Mean Square; alternating current value which corresponds to same direct current value that will produce same heating effect; also: in mathematics, averaging algorithm that results from square root of arithmetic mean of the squares.
RO—Reverse Osmosis; also: Receive Only, device that cannot transmit but only receive.
ROA—Return on Assets; net income divided by total assets; indicates how profitable a company is relative to its total assets.
Robotics—Study of design and use of robots, particularly for their use in manufacturing and related processes; they generally react to sensory input to perform high-precision or dangerous jobs; term coined by Isaac Asimov in science fiction book “I, Robot.”
Robotic Simulation & Control Software (RSCS)—Computing software for motion-intensive robotics from Robotics simulation software, Robotic off-line programming software, PC-based robot control software.
Robust—In reference to a product, one that doesn't break or fail easily such as an operating system in which any individual application can fail without disturbing the operating system or other applications; also: sometimes used to mean a product or solutions designed with a full range of capabilities.
ROC—Rate Of Change; Return On Capital (investment).
ROCE—Return On Capital Employed; indicator of profitability of capital investments; determined by dividing Earnings Before Interest and Taxes by (capital employed plus short-term loans minus intangible assets); ratio should at least be greater than cost of borrowing.
ROE—Return On Equity; net income divided by shareholder’s equity; measure of profitability generated with money invested.
RoHS—Restriction Of the use of certain Hazardous Substances in Electrical and Electronic Equipment directive (European Union); 2002/95/EC directive of European Parliament and Council, dated January 27, 2003, restricts use of certain hazardous substances in certain electrical and electronic equipment in most environments, installations and applications; directive also describes certain other environments, installations and applications where restrictions do not apply; where applicable, RoHS directive requires that electrical and electronic equipment placed on the market after July 1, 2006 not contain certain substances.
ROI—Return On Investment; efficiency of investment; total ROI of a system implementation is the total increase in profitability that can be attributed to the system, including cost reductions, increased productivity and increased sales, minus the total cost for the system including license fees, implementation costs, maintenance and training.
ROLAP—Relational On-Line Analytical Processing, see OLAP.
ROM—Read Only Memory; storage device with permanent memory; cannot write over, and will not change during system operation; also: Rough Order of Magnitude.
Room Conditions—Ambient environmental conditions under which equipment must commonly operate.
Rootkits—Originated as regular software applications, intended to take control of a failing or unresponsive system, but in recent years have been largely malware to help intruders gain access to systems while avoiding detection; consists of a program (or combination of several programs) designed to hide or obscure the fact that a system has been compromised, often as Trojans thus fooling users into believing they are safe to run on their systems; may install a 'backdoor' in a system by replacing the login mechanism with executable that accepts a secret login combination which in turn allows an attacker to access the system regardless of changes to the actual accounts on the system; they have been around on UNIX for many years, but started showing up for Windows about 2002 as well as Linux, Mac OS, and Solaris.
Ropushers—Vendor named category of control system specifications written by users & system consultants which require itemized fixed price quote valid for a year, based on preliminary specifications, estimated point counts, and drawings which will be added later; see also Dowatchados, Druthers, Expectifications, Gotchas, Smokescreens, Stickits, Stonecutters, Wannagirls. J
ROS—Return On Sales.
ROSE—Remote Operations Service Element; ISO9072.
Routing—Process (done by Router) of selecting correct circuit path for message; employs bottom three OSI layers to interconnect dissimilar networks; routers are smarter than bridges, are unaffected by differences in access protocol or topology among subnetworks; a bridge will "know" where specific destination (address) of a data packet, a router can only "know" next router; in manufacturing, a form that lists sequence of operations required for fabrication of product; list of instructions of sequential operations to fabricate a part, or perform a batch process.
Routing Information Protocol (RIP)—In communications, simple routing protocol that is part of TCP/IP protocol suite; determines route based on smallest hop count between source and destination; a distance vector protocol that routinely broadcasts routing information to its neighboring routers and is known to waste bandwidth; AppleTalk, DECnet, TCP/IP, NetWare and VINES all use incompatible versions of RIP.
RP—Rapid Prototyping; using ultraviolet cured photopolymers to build up three-dimensional solid objects in layers from 3-D CAD database, to give designer ability to have accurate physical representation of a part in matter of hours or days without expensive tooling.
RPC—Remote Procedure Calls; in computing equipment, to access other networked applications and, from interactive window, view its files without “closing out” of documentation system; used to pass processing work from busy systems to less busy systems (often “remote”), or from systems that lack specific functionality to systems that have that functionality.
RPG—Report Program Generator; computer language created by IBM® and generally considered non-procedural for producing business reports.
RPM—Revolutions Per Minute.
RPN—Reverse Polish Notation; programming form of Postfix notation in which operands are entered before operators, for example, a*(b+c) in Reverse Polish Notation is abc+*; see Polish Notation, Postfix.
RPO—Real-time Process Optimization & Training; see definition.
RPU—Remote Processing Unit; in which control and other actions are processed in various distributed locations, communicating these actions over a data highway to operators, central information point, etc.
RS—Recommended Standards; (RS-series specs) published by EIA, that define various electrical and mechanical interfaces for use with data communication equipment; now identified as EIA- series.
RS 232—TIA/EIA standard that specifies interface between data terminal equipment and data communication equipment employing serial binary data interchange, usually between computers and peripheral devices (modem, mouse, etc.); using a 25-pin DB-25 or 9-pin DB-9 connector, its normal cable limitation of 50 feet can be extended to several hundred feet with high-quality cable; defines purpose and signal timing for each of the 25 lines; however, many applications use less than a dozen; in 1984, this interface was officially renamed TIA/EIA-232; see TIA/EIA-574.
RS 422—TIA/EIA standard that specifies electrical characteristics of balanced voltage digital serial interface circuits that extend distances and speeds beyond RS-232; a balanced system requiring more wire pairs than its RS-423 counterpart and is intended for use in multipoint lines; both use either 37-pin connector defined by RS-449 or 25-pin connector defined by RS-530.
RS 423—TIA/EIA standard that specifies electrical characteristics of UNBALANCED voltage digital interface circuits.
RS 449—TIA/EIA standard that specifies general-purpose 37-pin and 9-pin interface for data terminal equipment and data circuit-terminating equipment employing serial binary data interchange; defines 37-pin connector for RS-422 and RS-423 circuits.
RS 530—TIA/EIA standard that defines 25-pin connector for RS-422 and RS-423 circuits; allows for higher speed transmission up to 2Mbits/sec over same DB-25 connector used in RS-232, but is not compatible with it.
RS 485—TIA/EIA standard that specifies electrical characteristics of generators and receivers for use in balanced digital multipoint systems that can be implemented with as little as a wire block with four screws or with DB-9 or DB-37 connectors; by using lower-impedance drivers and receivers, RS-485 allows more nodes per line than RS-422.
RSA—Rivest-Shamir-Adleman, inventors of the RSA cryptosystem; in digital communication, highly-secure cryptography method by RSA Data Security, Inc. using two-part key: private key is kept by owner and public key is published; data is encrypted by using recipient's public key, which can only be decrypted by recipient's private key; very computation intensive, thus it is often used to create a digital envelope, which holds RSA-encrypted DES key and DES-encrypted data in which secret DES key is encrypted for transmission over network, but encrypts and decrypts actual message using much faster DES algorithm; also used for authentication by creating a digital signature where sender's private key is used for encryption, and sender's public key is used for decryption.
RSCS—Robotic Simulation & Control Software, see definition.
RSI—Repetitive Strain Injury; another term for Cumulative Trauma Disorder, see CTD; also: (Romanian Standards Institute), member of IEC.
RSLD—Received Line Signal Detector; modem interface control signal (typically EIA RS232/422).
RSM—Remote Switching Module; also: Remote System Manager, a DEC® product built on DECnet™ which allows Micro VAX IIs and VAX stations to perform file sharing and electronic mail.
RSP—Remote Set Point; to a process control loop, typically comes from an output of another device.
RSS—Really Simple Syndication; syndication format developed by Netscape in 1999 and became very popular for aggregating updates to blogs and the news sites; also: Rich Site Summary; also: RDF Site Summary; family of XML file formats for web headline syndication used by news websites and weblogs in which headlines and links to the actual content are made available to other Web sites; after publishing site creates RSS file of its content, other Web sites may use headline feed, and content can be read with standard Web browser or by specialized RSS viewers; a.k.a. News Feeds a.k.a. Web Feeds; there are two lineages: RSS 1.0 conforms to the W3C's RDF specification and was released from the RSS-DEV Working Group in 2000 (see RDF); RSS 2.0, which evolved from Netscape's Versions 0.90 & 0.91 along with Radio Userland's Versions 0.92 and 0.94, eventually released by Harvard Law School in 2003; most news viewers support both formats.
RSTP—Rapid Spanning Tree Protocol; see definition.
RT—Real Time; see definition.
RTB—Resistance Thermometer Bulb; temperature measuring device in which expansion and contraction of a fill, such as mercury and certain other gasses and liquids, is calibrated to reflect change in temperature.
RTC—Real-Time Clock, typically battery backed; also: Real-Time Consortium, formed in 1990, proposed OBIOS standard.
RTD—Resistance Temperature Detector; temperature measuring device in which resistance of sensing element is an accurately known function of temperature.
RTDR—Real Time Database Repository.
RTF—Rich Text Format; format method of saving data to electronic memory expressly for exchanging data between computers.
RTL—Resistor-Transistor Logic; also: Run-Time Library.
RTO—Real Time Optimization; see definition.
RTOS—Real Time Operating System; software of computer that controls execution of application programs which allow immediate interaction with data as it is created, as in process control system.
RTP—Rapid Thermal Process; see definition.
RTPM—Real-Time Process Management; results of integrating real-time process data from DCSs with business management information systems (MIS).
RTS—Request To Send; modem interface control signal (typically EIA RS232/422) indicating readiness to send data to DCE.
RTSE—Reliable Transfer Service Element.
RTSS—Real Time SubSystem; in computer software, that part of the operating system that runs all of its threads before any NT threads.
RTU—Remote Termination Unit, see definition; sometimes called Remote Terminal Unit or Remote Telemetry Unit; also: Real time Unit; also: Real Time UNIX; also: Reaction Tank Unit; also: Receiver/Transmitter Unit; also: Redundant Transfer Unit; also: Remote Test Unit; also: Remote Thermal Unit.
RTV—Real-Time Video; in video development, DVI™ or INTEL® i750-based algorithm for symmetric data compression.
RTX—Real-Time eXecutive; also: Real Time eXtension.
Rugged—Too heavy to lift. J
Rule-Based System—Functional system in which knowledge is stored as simple if-then or condition-action rules.
Rule of Thumb—Comes from historical common law entitlement of a man to beat his wife (children, underlings) with a switch, provided its measurement was "no thicker than his thumb". K
Run Chart—In SPC, sometimes called the individual measurements chart, this shows progress of a monitored characteristic or attribute (y-axis) as a function of time (x-axis).
Run-around—In typographical composition of screen displays and printing, the term describing type set to fit around a picture or other element of the design.
Running Head—In typographical composition of screen displays and printing, a headline or title repeated at top edge of each page.
Runtime—In computing, time during which data is fetched by control unit (CPU) and actual processing is performed in arithmetic logic unit (ALU); also: time during which program is executing.
Run Time Controller—In process control, implementation tool, which includes neural network model executor for prediction and neural network model inversion engine for control or optimization; can be used to implement a prediction model.
RVI—ReVerse Interrupt; in digital communication, control character transmitted by receiving station to request termination of current transmission because it must send another high priority message.
RxD—Receive Data, digital data signal input, usually to receiver from computer transmitter.
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