Automating Manufacturing Systems - Process Control and ...

plc glossary - 35.13
floating point - uses integer math to represent real numbers.
flow chart - a schematic diagram for representing program flow. This can be used during design of software,
or afterwards to explain its operation.
flow meter - a device for measuring the flow rate of fluid.
flow rate - the volume of fluid moving through an area in a fixed unit of time.
fluorescence - incoming UV light or X-ray strike a material and cause the emission of a different frequency
light.
FM (Frequency Modulation) - transmits a signal using a carrier of constant magnitude but changing
frequency. The frequency shift is proportional to the signal strength.
force - a PLC output or input value can be set on artificially to test programs or hardware. This method is not
suggested.
format - 1. a physical and/or data structure that makes data rereadable, 2. the process of putting a structure
on a disk or other media.
forward chaining - an expert system approach to examine a set of facts and reason about the probable
outcome.
fragmentation - the splitting of an network data packet into smaller fragments to ease transmission.
frame buffers - store the raster image in memory locations for each pixel. The number of colors or shades of
gray for each pixel is determined by the number of bits of information for each pixel in the frame
buffer.
free field - a sound field where none of the sound energy is reflected. Generally there aren’t any nearby
walls, or they are covered with sound absorbing materials.
frequency - the number of cycles per second for a sinusoidally oscillating vibration/sound.
friction - the force resulting from the mechanical contact between two masses.
FSK (Frequency Shift Keying) - uses two different frequencies, shifting back and forth to transmit bits
serially.
FTP (File Transfer Protocol) - a popular internet protocol for moving files between computers.
fudge factor - a number that is used to multiply or add to other values to make the experimental and
theoretical values agree.
full duplex - a two way serial communication channel can carry information both ways, and each character
that is sent is reflected back to the sender for verification.
fuse - a device that will destruct when excessive current flows. It is used to protect the electrical device,
humans, and other devices when abnormally high currents are drawn. Note: fuses are essential
devices and should never be bypassed, or replaced with fuses having higher current rating.
35.7 G
galvonometer - a simple device used to measure currents. This device is similar to a simple DC motor.
gamma rays - high energy electromagnetic waves resulting from atomic fission or fusion.
gate - 1. a circuit that performs on of the Boolean algebra function (i.e., and, or, not, etc.) 2. a connection
between a runner and a part, this can be seen on most injection molded parts as a small bump
where the material entered the main mold cavity.
gateway - translates and routes packets between dissimilar networks.
Geiger-Mueller tube - a device that can detect ionizing particles (eg, atomic radiation) using a gas filled
tube.
global optimum - the absolute best solution to a problem. When found mathematically, the maximum or
minimum cost/utility has been obtained.
gpm (gallons per minute) - a flow rate.
grafcet - a method for programming PLCs that is based on Petri nets. This is now known as SFCs and is part
of the IEC 1131-3 standard.
gray code - a modified binary code used for noisy environments. It is devised to only have one bit change at
any time. Errors then become extremely obvious when counting up or down.
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