Rockwell Automation Publication 48CR-UM001A-EN-P - November 2019
169
Glossary
ladder orientation
A linear symbol orientation in which the bars are parallel to the direction of
travel of the symbol.
light-emitting diode (LED)
A semiconductor device that emits light when conducting current.
lens
A transparent piece of material with curved surfaces that either converge or
diverge light rays.
machine vision
The automatic acquisition and analysis of images to obtain desired data for
controlling a specific activity.
multi-drop
A communications protocol for networking two or more imagers or other devices
with a concentrator (or controller) and characterized by the use of individual
device addresses and the RS-485 standard.
noise
Any unwanted electrical signal that interferes with the read and transfer of an
image by the imager.
normally closed (N.C.)
A discrete output state that is only active when open.
normally open (N.O.)
A discrete output state that is only active when closed.
object plane
An imaginary plane in the field of view, focused by the optical system of an
imager at the corresponding image plane on the sensor.
output
A channel or communications line. Data or discrete signals that a device
transmits or displays.
parity
An error detection routine in which one data bit in each character is set to 1 or 0
so that the total number of 1 bits in the data field is even or odd.
picket fence orientation
A linear symbol orientation in which the bars are perpendicular to the direction
of travel of the symbol.
pitch
Rotation of a linear or 2D symbol around an axis parallel to the symbol length on
the Substrate.
pixel
An individual element in a digitized image array; “picture element”.
port
Logical circuit for data entry and exit. (One or more ports can be included within
one connector.)
processing time
The time that is used by a vision system to receive, analyze, and interpret image
information. Often expressed in parts per minute.
programmable logic controller
(PLC)
An electronic device that is used in industrial automation environments such as
factory assembly lines and automotive manufacturing facilities.
progressive scan
A non-interlaced scan that doubles the number of visible picture lines per field by
displaying all picture lines at once.
