JAOMAD Glossary F:
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
F—In thermometry, degrees Fahrenheit; also: means "Flow Rate" when used in first alpha character position of ISA instrument function tag, means "Ratio"(Fraction) when used in modifier position [see ANSI/ISA S5.1-1984 (R1992)]; also: f (lowercase) in math is abbreviation "femto-" for 10-15.
F&G—Fire & Gas; usually in reference to Emergency Shut Down applications.
Factorial Designs—Designs of experiments in which multiple input variables are varied simultaneously at two or more discrete levels in every possible combination.
Factory Calibration—Tuning or altering of control circuit or device by manufacturer to bring it into specification.
FAIS—[pronounced: fice] Factory Automation Interconnection System; initially a Japanese effort to commercialize Mini-MAP subsystem optimized for manufacturing cell network applications.
Fall Time—Time required for trailing edge of pulse to fall from 90% to 10% of its amplitude; time required for a component to produce such a result.
Fan-in—Maximum number of electrical inputs acceptable by a logic circuit.
Fan-out—Within family of logic circuits, maximum number of electrical inputs to other circuits that output or given circuit can drive.
FAQ—Frequently Asked Questions; term usually associated with the Internet.
FAR—Failure Analysis Report.
Farsang—Linear measure of about four miles used 4,000 years ago in Babylon, also known as parasang(es). K
FAS—Fieldbus Access Sublayer; see definition.
Fast Ethernet—[100BaseT] Version of Ethernet (IEEE 802.3u standard) which transmits at 100 Mbps rather than 10 Mbps; all nodes share the 100 Mbps bandwidth and use same CSMA/CD access method as regular Ethernet with some modification. Three cabling variations are provided. 100BaseTX uses two pairs of Category 5 UTP, 100BaseT4 uses four pairs of Category 3, and 100BaseFX uses multimode optical fibers and is primarily intended for backbone use.
FAT—Factory Acceptance Testing (of control systems before they leave supplier’s factory); see SAT.
Fat 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, Rich Client; see Thin Client for contrast.
Fault Tolerant—Ability of system to continue executing tasks regardless of strategic component failure, but perhaps with less effectiveness or somewhat diminished performance and/or functionality.
FC—Fail Closed; Default mode of final element in a process, typically a valve.
FCC—(Federal Communications Commission); U.S. agency involved with any radio-transmitted communications and equipment, which can interfere with them; also: Flat-Conductor Cable.
FC-CBGA—Flip Chip Ceramic Ball Grid Array.
FCFS—First Come, First Served; order of packet transmissions in multiple access to linear bus LANs, where stations may place reservations in a separate logical channel (as compared with round robin method).
FC-PBGA—Flip Chip Platic Ball Grid Array.
FCS—Frame Check Sequence method of transmission error detection; also: Field(bus) Control System, where network for control system is a fieldbus between controllers and HMI as well as between controllers, and even where parts of controller is scattered among various devices along the fieldbus; also: Fieldbus Communication Services, see definition.
FDA—(Food and Drug Administration); U.S. agency involved with validation of all systems and facilities manufacturing food, pharmaceutical and medical related products for human or animal use.
FDC—Final Control Device, such as valve, motor drive unit, SCR, etc.; see Final Element; also: Factory Data Collection.
FDDI—Fiber Distributed Data Interface; ANSI standard for fiber optic links with data rates to 100 Mbps; two 50Mbs counter rotational token rings, synchronous, prioritized; see CDDI.
FDDI-II—Variant to FDDI that supports isosynchronous traffic.
FDI—Failure Detection and Identification routines.
FDMA— Frequency Division Multiple Access; technology used in analog cellular telephone network that divides spectrum into 30KHz channels. See TDMA, CDMA, CDPD.
FDM—Frequency Division Multiplexor; device that divides available transmission frequency range into narrower banks, each of which is used for separate channel; also: Fused Deposition Modeling, form of Rapid Prototyping, see RP; also: Fused Disposition Modeling, see definition.
FDT—Field Device Tool (Technology); standardizes communication interface between process control field devices and control systems independently from the communication protocol (fieldbus) and software environment of either the device or the host system to allows any device to be accessed from any host through any protocol; allows single method to configure any supplier’s field device on any field bus through any supplier’s control system; also: Fire Dynamics Tool.
FDT/DTM—Field Device Tool/Device Type Manager; two essential parts of FDT technology are FDT frame application and device type managers which are available for field devices and communication equipment, allowing simple functioning like Print Manager in Windows Office program and the Print Drivers that must be installed to make different printers work and providing graphical user interface for their configuration; see DTM.
FDT JIG—Field Device Tool Joint Interest Group of companies formed to provide customers with more convenient, standards - compliant methods for configuring a wide range of process instruments.
FDX—Full DupleX; mode of communication in which data may simultaneously flow in both directions (4-wire).
FEA—Finite Element Analysis software for design; also: Finite Element Analysis, see definition.
Fed. Reg.—Federal Register; daily U.S. government publication detailing proposed and final rules and other federal business.
FED—Field Emitter Display; see definition.
FEED— Front-End Engineering Design.
Feedback—In process control, sensing change in output of process to cause change in control signal to one of the inputs to that same process; also called closed loop control.
Feedforward—In process control, sensing change in input of process to cause change in control signal to one of the other inputs to that same process; does not have self correcting action as with Closed Loop (Feedback) Control; also called open loop control or anticipatory control.
Feedthrough—Contact on printed circuit board that connects one physical layer of interconnections with the next, passing through insulating material that separates them.
FEP—Front End Processor; dedicated processor to perform communication functions to off load other processors within same device; it is that portion of system which first receives process or plant data, usually for signal conditioning and/or multiplexing; also: Fluorinated Ethylene-Propylene (Teflon).
FERC—(Federal Energy Regulatory Commission); an independent agency that regulates the interstate transmission of natural gas, oil, and electricity as ell as regulates natural gas and hydropower projects, and oversees energy industries in the economic, environmental, and safety interests of the American public.
Ferrite—Low density ceramic material with composition that includes divalent metal, such as cobalt, nickel, maganese, or zinc; cores made from these have very low eddy current loss and are useful in some mechanical-to-current transducers as well as in high frequency circuits and as magnetic dust cores in computers.
Ferroresonant Power Supply—Power supply using ferroresonant regulator consisting of ferroresonant transformer ac tuning capacitor, rectifier, and dc filter capacitor to provide reasonable line voltage regulation which is the least expensive yet most reliable because of the simple circuit.
FET—Field Effect Transistor; unipolar multielectrode semiconductor device in which current flows through narrow conducting channel between two electrodes and is modulated by electric field applied at third electrode.
FF—Form Feed; also: Flat Faced; also: means "Flow Ratio" when used in first two alpha character positions of ISA instrument function tag [see ANSI/ISA S5.1-1984 (R1992)]; also: Fieldbus Foundation, a not-for-profit organization dedicated to developing single, worldwide, interoperable fieldbus... formed from merger of WorldFIP North America and ISP Foundation in 1994.
FFF—Fused Filament Fabrication, see definition.
FFT—Fast Fourier Transform; in digital signal processing (DSP), algorithm for reducing amount of calculation necessary to compute a Fourier Transform.
Fiber Channel—Emerging optical communication standard by an ANSI working group; 100 MBytes/second.
Fiber Loss—Attenuation (deterioration) of light signal in optical fiber transmission.
Fiber Optic Inter Repeater Link—Early implementation of subset of IEEE 802.3 10BaseFL standard designed to connect fiber optic repeaters at 10Mbps; used by various Ethernet manufactures to produce network and port interface cards as well as MAUs/transceivers.
Fiber Optics—Transmission technology in which modulated light wave signals, generated by laser or LED, are propagated along (typically) glass or plastic medium, then demodulated to electrical signals by light sensitive receiver.
FIC—Fieldbus Implementation Consortium; to implement SP50 as it evolves.
FICIM—Fieldbus Integration into CIM; ESPRIT project group 5206.
FID—Flame Ionization Detector.
Field—In record keeping, predetermined section of a record; that part of computer record containing some specific portion of information.
Field Emitter Display (FED)—Flat panel display that works similar to CRT, shooting electrons at colored Phosphors (pixels) to create image on screen, but rather than illuminate phosphors with single electron gun, "flat cathode" chip is placed behind each phosphor, allowing use of flat panel in lieu of bulky picture tube; see Organic Light Emitting Diode.
Field of View—Volume in space defined by angular cone extending from focal plane of an instrument or video screen.
Field Power—Electrical power that is connected to an actuator or other device, typically 24,120, or 240 volts, that is also connected to controlled electrical contact or device which is part of actual control system.
Field Programmable—Timers and counters that have user programmable parameters such as time/count ranges and output sequences; units are often programmed by miniature rocker switches located inside timer or by jumper wires to different connection points.
Field Programmable Gate Array (FPGA)—Type of gate array that is programmed in the field rather than during semiconductor fabrication; containing up to hundreds of thousands of gates, there are a variety of FPGA architectures on the market. some are very sophisticated, including not only programmable logic blocks, but programmable interconnects and switches between the blocks; interconnects take up a lot of FPGA real estate, resulting in a chip with very low gate density compared to other technologies; vast majority of FPGAs are SRAM-based, although there are some flash and antifuse versions.
Field Tested—We don't have the equipment to test it at the factory. J
Field/Frame—In NTSC video development, each frame has two fields, one for every even scan line and the other for every odd scan line, so NTSC 60 fields and 30 frames per second.
Fieldbus—Digital, serial, multidrop, two-way communication path between intelligent industrial field equipment such as sensors, actuators, controllers and even control room devices which serve as Local Area Network (LAN) for advanced process control; designed to replace simple 4-20 mA field signals with bi-directional, multivariable data communications capability; also: specific ISA SP50 (FOUNDATION Fieldbus) standard for digital communications operating at lowest level of data communications (I/Os) in automation systems; it allows communication and interoperability among "smart" field devices and control system devices from multiple vendors; it also supports information access for monitoring, control, and alarm tasks during plant startup, operation, and maintenance; as this standard is developing and gaining interest, two versions are emerging: H1 for linking sensors, actuators to control devices, HSE for functioning more as full blown data highway on more sophisticated scale; see Fieldbus Architecture, below.
Fieldbus Access Sublayer (FAS)—In FOUNDATION Fieldbus technology, maps Fieldbus Message Specification (FMS) onto Data Link Layer (DLL).
Fieldbus Architecture—Control architecture that uses digital, serial, multidrop, two-way communications between and among intelligent field devices and control/monitoring systems; there are several different “competing” types; generally considered communicating large, “block level” messages of high function among sophisticated devices at low speeds over “long” distances, as defined by Automation Research Corporation (ARC), see also Sensorbus, Devicebus.
Fieldbus Communication Services—In Fieldbus Foundation context, messaging sublayer that application layer provides to access remote application process objects and their Object Directory descriptions.
Fieldbus Foundation—Non-profit consortium of instrumentation and controls suppliers that has been and is developing a standard digital communication network (fieldbus) based on SP50 standard for process control applications; network being developed is called FOUNDATION Fieldbus.
Fieldbus Messaging Specification (FMS)—In FOUNDATION Fieldbus technology, contains definitions of Application Layer services in FOUNDATION fieldbus; specifies services and message formats for accessing Function Block (FB) parameters, as well as Object Dictionary (OD) descriptions for those parameters defined in the Virtual Field Device (VFD).
FI—Fail Indeterminate; default mode of a final element in a process, typically a valve.
FIFO—First In First Out; memory buffer in which first data stored is first data sent.
File Server—Digital mass storage device that can be accessed by several computers, providing common sharing of stored data.
File—In computers, set of related records or data treated as single unit; also: document that has been saved with unidentifiable name, thought of as something stored in a file cabinet in foreign language folders, except when you try to remove file, file cabinet gives you electric shock and tells you that file format is unknown. J
Film Resistor—Type of resistor that uses thin layer of resistive material deposited on insulating core; for low power applications these are more stable than composition resistors and smaller, less expensive than the more accurate wire wound resistors.
Filter—In digital signal processing (DSP), circuit that reduces noise and other unwanted elements of signal.
Filtering—Protection from "background Noise" that could alter or destroy data transmission.
Final Element—(Final Device, Final Control Device) In process control, last device in control loop which causes change in the process, such as valve, motor drive unit, SCR, solenoid, etc.
Finger—Internet software tool for locating people on other Internet sites.
Finite Element Analysis (FEA)—Consists of a computer model of a material or design that is stressed and analyzed for specific results. It is used in new product design, and existing product refinement.
FInt—Fieldbus International; formed as successor to Norwegian Fieldbus Consortium.
FIP—Factory Instrumentation Protocol; a French national field bus standard (1Mbs) to link sensing actuators, and controllers in automation systems, supported by over 125 European companies.
FIPA—(Foundation for Intelligent Physical Agents); IEEE Computer Society standards organization that promotes agent-based technology and the interoperability of its standards with other technologies.
FIPS—Federal Information Processing Systems.
Firewall Technology—In computer based networks, security protection system designed to prevent unauthorized access to or from of database and files within private network: can be implemented in both hardware and software, or a combination of both; frequently used to prevent unauthorized Internet users from accessing private networks connected to Internet, especially intranets; all messages entering or leaving intranet pass through firewall, which examines each message and blocks those that do not meet specified security criteria; see also Packet Filter, Application Gateway, Circuit-level Gateway, Proxy Server.
Firewire®—High speed, low cost computer network technology developed by Apple Computer and now covered by IEEE 1394 which permits several electronic devices to communicate; made up of six individual cables - one for power, one for ground, two for data, and two for strobe, which synchronizes the data; assembly is shielded; also called iLINKTM by Sony Corporation.
FIR—Finite Impulse Response filter; in digital signal processing (DSP), filter which has output determined by its coefficients and previous inputs, characterized by having linear phase response; see IIR.
Firmware—Computer program or software which constitutes fundamental part of specific system function and is stored permanently in PROM or ROM or semi-permanently in EPROM; "software that acts like hardware;" not to be confused with “Vaporware,” which is computer software that is announced or advertised, but never shipped; see Software; Hardware; Wetware.
FIS—Financial Information System, computer database of customer and vendor accounts used in EIS.
FISCO—Fieldbus Intrinsic Safety Standard.
FIT—Failures In Time; also: Failure unITs, number of failures of a device in a given time, frequently expressed in failures per billion (109) hours.
Fixed Palette—In context of Internet, established palette on Web browser which converts graphic images to its own colors, not those colors from original image.
Fixed Point—Pertaining to number system in which each number is represented by single set of digits and its base (position of radix point) is implied by manner in which numbers are used; see Floating Point.
FIX—Financial Information eXchange; financial services computer communication standard.
Flag—Any of various types of indicators used for identification of condition or event; for example in communications, bit pattern of six consecutive "1" bits (character representation is 01111110) used in many bit-oriented protocols to mark beginning (and often end) of the frame.
Flash ADC— High speed ADC whose output code is determined in a single step by banck of comparitors and encoding logic.
Flash Memory—One of first applications of PCMCIA cards; Type I card (see PCMCIA) containing up to 20MB RAM and small battery so memory is retained when unplugged from any power, as alternative to floppy disks; much faster than floppy or hard disks allowing a device to turn on instantly with data intact but not durable enough to be used as main memory and break down gradually; also called Flash Card.
Flashover—Disruptive discharge in form of arc or spark between two electrical conductors or between conductor and earth (ground).
Flat File Database—Relatively simple database system in which each database is contained in a single table, adequate for many small applications; compare: Relational Database, Multidimensional Database.
Flat Tuning—Tuning with substantially equal response to range of frequencies.
Flatbed Scanner—Device that scans images in manner similar to photocopy machine where original art is positioned face down on glass plate.
FLC—Fuzzy Logic Controller.
Flexible Function Block—In FOUNDATION Fieldbus technology, similar to a Standard FB, except that function of block, order and definition of block parameters, and time required to execute block are determined by application-specific algorithm created by a programming tool; typically used for control of discrete processes and for hybrid (batch) processes; a Programmable Logic Controller (PLC) can be modelled as a Flexible Function Block device.
FLEXOS— In wireless technology, proprietary operating system designed for hand-held devices.
FL—Fail Locked; Default mode of final element in process, typically a valve.
Flicker—Flashing of video screen as electron beam, which creates image, follows its raster pattern.
Flight Risk—Used to describe employees who are suspected of planning to leave the company or department soon. J
Flip-flop—Half-shift register; bistable multivibrator circuit that usually has two inputs corresponding to two stable states; so called because appropriate pulse causes it to "flip" into and remain in one state, while pulse on other input will cause it to "flop" into other state.
Float—In process control, amount of time between completion of a task or activity and start of the next; also: in your checking account, same idea but with money. J
Floating Gate PROM—Optically erasable read-only memory.
Floating Point—Arithmetic notation in which decimal point can be manipulated, values are sign, magnitude and exponent; this is a form of number presentation in which quantities are represented by number called mantissa (significant digits) multiplied by power of number base; see Fixed Point.
Floating—In electrical circuitry, denotes circuit or device that is not connected to any source of potential.
Floppy Disk—In computers, flexible disk carrying magnetic medium in which digital data is stored for later retrieval and use, usually iron oxide coating on flexible substrate.
Flow Cases—Known conditions of flow.
Flow Control—In digital processing, procedure for regulating flow of data, once buffer of specific device has reached capacity.
Flow Manufacturing—Operations (Pull Manufacturing style, as differs from MRP) where production is based upon actual demand (orders); compare: Push Manufacturing, MRP.
Flow Rate—Actual speed or velocity of flow movement.
Flowchart—Diagrammatic representation of operations involved in algorithm or automated system; flow lines indicate sequence of operations or flow of data, and special standard symbols are used to represent particular operations.
Flowmeter—Device used for measuring flow or quantity of moving fluid.
Flow—Travel of fluids (liquids or gasses) in response to force, such as pressure or gravity; often is used to indicate movement of electrical energy (flow of electrons) and digital signals (flow of data).
Flush Left (or Right)—In typographical composition of screen displays and printing, type set to line up at left (or right) margin.
Flush Paragraph—In typographical composition of screen displays and printing, paragraph with no indentation.
Flying Lead—Wire lead which exits in back of connector hood on outside of cable jacket, normally attached to drain wire or shield and then connected to chassis of switch, modem, etc.; also: hardware control lead.
FM—Frequency Modulation; method of transmission in which carrier frequency varies in accordance with signal; also: in measuring devices, usually in form of deviation from center frequency, where deviation is proportional to applied stimulus; also: in electronic publishing and screen displays, digital screening process that converts images into very small dots of equal size and variable spacing, see Stochastic Screening, compare with AM screening; also: (Factory Mutual Research Corporation); organization which sets industrial safety standards, generally to protect the process; focused on fire safety and prevention; they test and approve products, and FM approval is recognized by OSHA as product which does not create fire hazard. Compare with UL.
FMCW—Frequency Modulated Continuous Wave; see definition.
FMEA—Failure Mode & Effects Analysis; a procedure by which every individual component is ranked with percentage failure values for each failure mode (i.e.: transistor short, open, drift, etc.) to determine their respective failures in time (FIT), then an overall impact is calculated for device in which all of these components are used; used in developing MTTF.
FMEDA—Failure Modes, Effects and Diagnostic Analysis; one of the steps taken to achieve functional safety certification of a device per IEC61508; analysis shows that Safety Instrumented System (SIS) designers can meet integrity requirements.
FMS—Fieldbus Messaging Specification; see definition.
FMS—Flexible Manufacturing System; also: Fieldbus Messaging Service, companion standard for Fieldbus application layer; also: Factory Management System; also: Factory Message Specification.
FNPT—Female National Pipe Thread.
Focus—In video displays, crispness of text and lines, contrast of adjacent single-pixel-wide black and white lines.
FO—Fail Open; Default mode of final element in process, typically a valve.
FOF—First Out Fault; system to determine accurately the sequence of alarms in process or plant.
FOG—Fat, Oil and Grease from wastewater in water treatment plants.
FOIRL—Fiber Optic Inter Repeater Link; early implementation of subset of IEEE 802.3 10BaseFL standard designed to connect fiber optic repeaters at 10Mbps; used by various Ethernet manufactures to produce network and port interface cards as well as MAUs/transceivers.
Foldback—In current limiting circuit of power supply, ability upon sensing overload to prevent damage to power supply, and can help to prevent damage to the load by turning current back to a low, safe level; sometimes called 'Re-entrant' Current Limiting.
Folio—In typographical composition of screen displays and printing, the page number.
Font—In typographical composition of screen displays and printing, complete assortment of letters, numbers, punctuation marks, etc. of given size and design.
Footlamberts—Unit of brightness in video displays.
Forceback—Back-calculation within algorithm function block to prevent signal "bump" during multitasking (switching between functions); particularly important in linking cascaded process control loops in microprocessor based controllers.
Form Factor—Physical specifications of device, such as rack mounts, etc.); evolved from relay terminology for contact configurations.
Format—In typographical composition of screen displays and printing, the size, style, type page, margins, printing requirements, etc.; also: in computer disks, to prepare disk so it can hold information in form recognized by computer operating system (Macintosh, PC, etc.); also: in computer data object rendition, form in which data is stored (saved) such as Text, Bit-mapped, etc.
Fortezza—[means "fortress" in Italian]; in digital communications, authentication system endorsed by National Security Agency that uses PC Card as authentication token; part of U.S. Government's GOSIP policy, and vendors must supply Fortezza-compliant products in order to win contracts; uses 56-bit key based on the DES encryption method.
FORTH—Computer language which should have been called FOURTH (4th generation) but astronomer/developer Charles Moore's computer accepted only 5-character names; this object oriented language was created to control telescopes, but its extendibility is key to its ever growing popularity, using "reverse Polish" notation, it contains applications useful in process control.
Forth-Generation Language (4GL), -Environment (4GE)—Computer language instructing computer at a higher-level language abstraction than traditional high-level programming languages; any computer language that does not require traditional input process/output logic will fall into this category.
FORTRAN—FORmula TRANslator; first high level computer language, developed by IBM® (1954); known as scientific language because of its facility for "number crunching," solving engineering, mathematical, and other scientific problems; procedure-oriented and has good array handling features.
Forward Channel—Data transmission channel in which direction of transmission coincides with that in which information is being transferred.
Forward Compatible—Designs which ensure compatibility with future versions.
Fourier Transform—In digital signal processing (DSP), algorithm for extracting frequency information from signal.
Four-wire Transmitters―See Type 4 analog (4-20mA) transmitters.
FOV—Field Of View (of sensors, especially optical).
FPD—Flat Panel Display; non-Cathode Ray Tube (CRT) displays, generally dominated by Liquid Crystal Displays (LCDs), Electroluminescent displays (ELs), and Plasma Display Panels (PDPs); older, but still widely used are Field Emitter Displays (FEDs); also: Field Programmable Device, see PLD; also: Flame Photometric Detector.
FP-EPSM—Functional Profiles for Electric Power Systems Messaging.
FPGA—Field Programmable Gate Array; programmable logic chip (PLD) with high density of gates; variety of architectures, some of which can be very sophisticated, including not only programmable logic blocks, but programmable interconnects & switches between blocks.
FPLA—Field Programmable Logic Array; see Programmable Logic Array.
FPM—Feet Per Minute (flow velocity); also: Fast Packet Multiplexing, technology which integrates synchronous and asynchronous data with voice and fax signals over composite channel, eliminating delays associated with standard packet multiplexing by giving priority to voice and fax signals over data signals.
FPMRAM—Fast Page Mode Random Access Memory; type of Dynamic RAM that allows faster access to data in same row or page; sometimes called page mode memory, works by eliminating need for row address if data is located in row previously accessed.
FPROM—Field Programmable Read Only Memory.
FPS—Feet Per Second, in flow velocity; Frames Per Second in video and computer imaging.
FPSO—Floating, Production, Storage and Offloading [oil, gas vessel].
FPU—Floating Point Unit; performs numeric calculations for the processor, specialized just for numeric calculations and can boost screen redraws, image filtering effects, spreadsheet calculations and similar operations by as much as 900%.
FQ—Means "Flow Quantity" when used in first two alpha character positions of ISA instrument function tag [see ANSI/ISA S5.1-1984 (R1992)].
Fractals—Lossy compression method used for color images; providing ratios of 100:1 or greater and is especially suited to natural objects, such as trees, clouds and rivers; method turns image into set of data and an algorithm for expanding it back to original; term comes from "fractus," which is Latin for broken or fragmented, and was coined by IBM Fellow and doctor of mathematics Benoit Mandelbrot, who expanded on ideas from earlier mathematicians and discovered similarities in chaotic and random events and shapes.
Fractional Factorial Designs—Subclass of factorial designs that reduce number of experiments to be performed by exploring only a fraction (such as one half) of the input variable space in a systematic manner.
FRAD—Frame Relay Access Devices.
Frame—Group of digits transmitted as single unit, over which coding procedure is usually applied for synchronization or error control purposes; also called Block.
Framework—In context of Graphical User Interfaces for Distributed Control Systems, vendor's organization of pre-established screen formats, hierarchies, navagation routines and alarm handling techniques, along with "instrument faceplates" singularly, in groups, and in overviews, which automatically populate based upon control strategies developed by user.
FRAM—Ferroelectric Random Access Memory is high density with high speeds of DRAM and SRAM and non volatility of ROM; Also called "Flash RAM," see Flash Memory.
Frequency—Number of cycles over specified time through which an event occurs; reciprocal is called the period.
Frequency Division Multiplexor (FDM)—Device that divides available transmission frequency range into narrower banks, each of which is used for a separate channel.
Frequency Domain—Mathematical construct that simplifies analysis of feedback control systems; can be used to show how closed-loop system will react to disturbance, setpoint change, or change in behavior of the process
Frequency Modulated Continuous Wave (FMCW)—Radar technology that continuously measures a mixed differential frequency as opposed to technology that measures only discrete periods of time; used for level measurement because of its superior signal processing capabilities.
Frequency Output—Output in form of frequency which varies as function of applied measurand.
Frequency Phase Control Regulation—Regulation technique in power supplies which usually employs SCRs and can control phase of either primary or secondary.
Frequency Response—Behavior of device output as function of input, both with respect to time.
Fresnel Reflection—Reflection that occurs at planar junction of two materials having different refractive indices; this is not function of angle of incidence.
Fresnel Zone—[pronounced: fraynel zone] pattern of electromagnetic radiation that is created by transmitting station from its antenna to receiving antennas; these visual line-of-sight that radio waves are in shape of an ellipsoid, or 3-D ellipse, which looks like an elongated (American) football; thus wireless signals do not travel only straight but spread out; Fresnel zone is an extra clearance around obsticals in addition to line-of-sight path.
Front End Processor—dedicated processor to perform communication functions to off load other processors within same device; it is that portion of system which first receives process or plant data, usually for signal conditioning and/or multiplexing.
Front End—Enigmatic term used by some to mean operator interface or application-specific aspects of computer program, defined by others to mean that part of control system directly connected to process sensors and instruments connected to the process.
Front Office Applications—Refers to applications designed for an organization's customer-facing departments such as sales, marketing and customer service and support.
FRP—Fiber Reinforced Plastic; sometimes used for instrument enclosures.
FSCM—Federal Stock Code for Manufacturers (US).
FSF—Fathom-Stone-Fortnight; hypothetical system of fundamental units used to indicate the antiquity of someone's thinking; see MKS. J
FSK—Frequency Shift Keying; simple modulation method of data transmission using frequencies to indicate state of bit being transmitted (two changes in frequency, one for 0, another for 1); see AM & PM.
FTA—Field Termination Assembly.
FTAM—File Transfer, Access, and Management; ISO protocol and part of MAP layer 7.
FTE—Fault Tolerant Ethernet.
FT-IR, FTIR—Fourier Transform InfraRed-based analyzer.
FTP—File Transfer Protocol; upper level TCP/IP service allowing files to be copied or moved across network, such as between desk-top PC and some mainframe computer; also: Foil-screened unshielded Twisted Pair wiring for electrical signals.
FTSA—Fault Tolerant System Architecture.
FUD—Fear, Uncertainty, and Doubt; what some vendor salesmen try to instill in customers about that vendor’s competition. J
Full Bridge—In strain gauges, such as in force or pressure sensors, all four legs of Wheatstone Bridge configuration are active in the development of a signal.
Full Duplex Transmission—Simultaneous two way communication between devices.
Full Scale Output—Algebraic difference between minimum output and maximum output.
Full-motion Imaging—Video image which is completely smooth; see Raster Imaging.
Fully Isolated Transmitters―Type 4 analog (4-20mA) transmitters used in a grounded circuit.
Function—Characteristic actions, operations, or kind of work performed by equipment (or people), such as the material handling function; also: the operation called for in by mechanical, electromechanical, electronic, or computing software instruction, such as the PID function; also: in computing software, set of software instructions executed by a single line of code that may have input and/or output parameters and returns a value when executed; also: in object oriented software, a program usually within an object.
Function Block Diagram (FBD)—Graphical language of programmable controllers which allows program elements (such as PID and other algorithms) that appear as blocks "wired" together in presentation similar to circuit diagram; one of five languages accepted under IEC 1131 standard for PLCs; see Instruction List, Ladder Logic, Structured Text, and SFC.
Function Blocks—Software modules, often firmware, which generally perform functions originally done in hardware elements, and form building blocks of control strategies; these are located in user layer of fieldbus standard.
Functional Requirement—Requirement that specifies some function that particular system or system component must be capable of performing; usually formally written, especially in process validation.
Functional Testing—In computer systems, also known as black box testing because source code is not needed; it involves input of normal and abnormal test cases and then evaluating outputs against those expected; can apply to computer software or to total system.
Furnace—Apparatus in which heat is liberated and transferred directly or indirectly to a solid or fluid mass; generally operate at ranges higher than ovens.
Fused Disposition Modeling (FDM)—A technique used in 3-D printing trademarked by Stratasys Inc.; generic version is called Fused Filament Fabrication (FFF); see Additive Manufacturing.
Fused Filament Fabrication (FFF)—An additive manufacturing technology commonly used in 3-D printing for modeling, prototyping, and production applications; see Additive Manufacturing.
Futurebus+—Fast standard for scale-able backplane interconnect; adapted by IEEE in Sept. 1991 with 32 or 64-bit, rate up to 175 MBps, no license fees.
Fuzzy Logic—Computing method used to model linguistic expressions (such as "somewhat more than") which have non-binary truth values; it has been used with PID algorithms in process control, especially where process relationships have been nonlinear; term coined by Lotfi Zadeh in his 1965 theory; used in feedback controller by E. H. Mamdani in 1974.
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