Glossary Terms
Terms that are used on the Manufacturing Automation website
Vector
A quantity that denotes both magnitude and direction. Vectors are commonly represented by a line segment with an arrow; the length represents the magnitude; the orientation in space and the placement of the arrow at one end of the line represents the direction.
Vector quantity
A quantity that denotes both magnitude and direction in relation to a given frame of reference. Examples of quantities that are vectors are displacement, velocity, force, and magnetic intensity.
Velocity
A vector quantity that denotes both magnitude (e.g., speed) and direction in relation to a given frame of reference.
Velocity loop
A feedback control loop in which the controlled parameter is motor velocity. Usually uses a tachometer for a feedback device.
VFD
Variable-Frequency Drive.
VGA
Video Graphics Adapter. A video adapter introduced in 1987. The VGA duplicates all video modes of the EGA (Enhanced Graphics Adapter) and provides several additional modes.
VRC Vertical redundancy check. An error-checking method that adds a check or parity bit to each character in a message so the number of 1 bits, including the parity bit, in each character is odd (odd parity) or even (even parity).
Virtual
The logical or conceptual view of something, which implies some sort of mapping function to get from conceptual to physical.
Vision systems
employ video cameras for inspection, verification, measurement, code reading and other purposes. Vision systems employ sophisticated pattern-recognition software to analyze the images they capture and compare it against defined patterns.
Voice recognition systems
Devices which are either portable and fixed station which use human speech as data input and translate it into machine recognizable codes or commands.
WACK
Wait before transmitting positive ACKnowledgment. In binary synchronous communications, this DLE sequence is sent by a receiving station to indicate that it is temporarily not ready to receive.
WAN
Wide-area network
Warehouse management systems
Software that integrates activities performed mechanically and by humans with an information system to effectively manage warehouse business processes and direct warehouse activities.
Watchdog timer
A timer that monitors a cyclical process and is cleared at the conclusion of each cycle. If the watchdog runs past its programmed time period, it will cause a fault.
Wavelength
The distance traveled by light (or other radiation) while completing one complete sine-wave cycle. It is expressed in nanometers (nm). Each color has a specific wavelength.
Weighted value
The numerical value assigned to any single bit as a function of its position in a word.
Window
A temporary, usually rectangular, bounded area on a CRT display that includes particular entities for entry, modification, or deletion.
Wireway
A trough, with hinged or removable covers; for housing and protecting electric wires and cables and in which conductors are laid in place after the wireway has been installed as a complete system. A wireway may be made of either sheet metal or of a flame-retardant nonmetallic material.
Word
A grouping or a number of bits in a sequence that is treated as a unit.
Word length
The number of bits in a word. In a programmable controller, unless stated otherwise, a word has 16 data bits.
Work
The magnitude of a force times the distance through which that force is applied. (work = force x distance)
Work area
A portion of the data table reserved for specific processor functions.
Workstation
1) A powerful stand-alone computer of the sort used in applications requiring considerable calculating or graphics capability. 2) A combination of input, output, and computing hardware that can be used for work by an individual. 3) A microcomputer or terminal connected to a network.
Wrap around
In a display, when data is moved in one direction through the display, or a cursor is moved though the data, as the data displayed or the cursor position reaches one extreme end, it jumps to the other extreme end so that the movement can continue.
Write
To load data into somewhere (memory, an output, another station).
x-axis
The axis of motion that is always horizontal and parallel to the work holding surface.
x-y matrix
A group of rows and columns. The x-axis is the horizontal row, and the y-axis is the vertical column. An x-y matrix is the reference framework for two-dimensional structures, such as mathematical tables, display screens, digitizer tablets, dot matrix printers and 2-D graphics images.
x-y-z matrix
A three-dimensional structure. The x and y axes represent the first two dimensions; the z axis, the third dimension. In a graphic image, the x and y denote width and height; the z denotes depth.
XML
Extensible markup
XMTR
Transmitter. A device that sends data.
XON/XOFF
An asynchronous communication protocol for the receiving station to control the flow of data from the transmitting station. When the receiving station cannot continue to receive any more data, as when its buffer is full, it transmits an XOFF (DC3) control character that tells the sender to stop. When the receiving station is again able to process more data, it transmits an XON (DC1) control character that tells the sender to resume transmission. This protocol is also referred to as software handshaking.
y-axis
See x-y matrix.
yaw
Angular rotation about the vertical axis, typically the Z-axis for X-Y-Z.
