Ferrule: A compressible tubular fitting that is compressed onto a probe inside a compression fitting to form a gas-tight seal.

FFT: Fast Fourier Transform. A computationally efficient mathematical technique which converts digital information from the time domain to the frequency domain for rapid spectral analysis.

Fiber Optics: A transmission medium consisting of thin strands of glass or plastic through which data is sent by means of pulse modulated light waves.

Field of View: A volume in space defined by an angular cone extending from the focal plane of an instrument.

FIFO Memory: A type of memory with separate input and output ports. The first data to enter the input port are the first to exit the output port.

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.

Filter: An electrical circuit that passes frequencies within a specified frequency band and attenuates signals that fall outside of that frequency band.

Firmware: Software instructions stored in ROMs.

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.

Floppy Disk: A small, flexible disk carrying a magnetic medium in which digital data is stored for later retrieval and use.

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.

Flush Diaphragm: Sensing element is located on the very tip of the transducer (NO pressure port).

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.

FPM: Flow velocity in feet per minute.

FPS: Flow velocity in feet per second.

Frame: A sequence of time slots in ISDN. A basic rate interface frame consists of 48 time slots repeated every 250 microseconds.

Freezing Point: The temperature at which the substance goes from the liquid phase to the solid phase.

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 Response: The range of frequencies over which the transducer voltage output will follow the sinusoidally varying mechanical input within specified limits.

Frequency: The number of cycles over a specified time period over which an event occurs. The reciprocal is called the period.

FTP: File Transfer Protocol. The Internet standard high-level protocol for transferring files from one computer to another.

Full Bridge: A Wheatstone bridge configuration utilizing four active elements or strain gages.

Full Duplex: Communications that takes place in both directions at the same time.

Full Scale: See Rated Capacity.

Full Scale Output: The algebraic difference between the minimum output (normally zero) and the rated capacity.

Functions: Three mode PID controller. A time proportioning 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.