Following is a definition of terms frequently used in the instrumentation, industrial automation and test & measurement communities.
Fahrenheit: A temperature scale defined by 32° at the ice point and 212° at the boiling point of water at sea level.
Ferrule: A compressible tubular fitting that is compressed onto a probe inside a compression fitting to form a gas-tight seal.
Field Balancing Equipment: An assembly of measuring instruments for performing balancing operations on assembled machinery which is not mounted in a balancing machine.
Field of View: A volume in space defined by an angular cone extending from the focal plane of an instrument.
File: A set of related records or data treated as a unit.
Filling Solution: A solution of defined composition to make contact between an internal element and a membrane or sample. The solution sealed inside a pH glass bulb is called an internal filling solution. This solution normally contains a buffered chloride solution to provide a stable potential and a designated zero potential point. The solution which surrounds the reference electrode internal and periodically requires replenishing is called the reference filling solution. It provides contact between the reference electrode internal and sample through a junction.
Firmware: Programs stored in PROM’s.
Flag: Any of various types of indicators used for identification of a condition or event; for example, a character that signals the termination of a transmission.
Flow Rate: Actual speed or velocity of fluid movement .
Flow: Travel of liquids or gases in response to a force (i.e. pressure or gravity).
Flowmeter: A device used for measuring the flow or quantity of a moving fluid.
FM Approved: An instrument that meets a specific set of specifications established by Factory Mutual Research Corporation.
FM: Factory Mutual Research Corporation. An organization which sets industrial safety standards.
Forced Vibration: Vibration of a system caused by an imposed force. Steady-state vibration is an unchanging condition of periodic or random motion.
FORTRAN: Formula Translation language. A widely used high-level programming language well suited to problems that can be expressed in terms of algebraic formulas. It is generally used in scientific applications.
FPM: Flow velocity in feet per minute.
FPS: Flow velocity in feet per second.
Freezing Point: The temperature at which the substance goes from the liquid phase to the solid phase.
Frequency Modulated Output: A transducer output which is obtained in the form of a deviation from a center frequency, where the deviation is proportional to the applied stimulus.
Frequency of Vibration: The number of cycles occurring in a given unit of time. RPM – revolutions per minute. CPM- cycles per minute.
Frequency Output: An output in the form of frequency which varies as a function of the applied input.
Frequency, Natural: The frequency of free (not forced) oscillations of the sensing element of a fully assembled transducer.
Frequency: The number of cycles over a specified time period over which an event occurs. The reciprocal is called the period.
Full Bridge: A Wheatstone bridge configuration utilizing four active elements or strain gages.
Full Scale Output: The algebraic difference between the minimum output and maximum output.
Functions: Three mode PID controller. A timeproportioning controller with integral and derivative functions. The integral function automatically adjusts the system temperature to the set point temperature to eliminate droop due to the time proportioning function.