Rockwell Automation 1756-HSC ControlLogix High Speed Counter Module User Manual
Page 118
Publication 1756-UM007C-EN-P - November 2011
118 Glossary
• Rotary encoder—is a feedback element that converts rotary position
(absolute or incremental) into a digital signal. Often, the directly
measured rotary position is used to determine a linear position through
gearing.
• Absolute encoder—is a feedback element that generates a digital code
that is unique for each absolute position (linear or rotary). An absolute
encoder usually provides the digital feedback signal in a Gray code to
minimize errors.
• Incremental encoder—is a feedback element that generates a digital
signal to indicate each incremental change of position (linear or rotary).
An incremental encoder usually provides the digital feedback signal in
quadrature form to indicate direction of motion.
encoder bandwidth An expression for maximum encoder speed in Hz. May also refer to the
maximum rate at which the control loop can accept encoder signals. The actual
bandwidth of the encoder and the capability of the controller to process
encoder signals may not be the same.
exact match An electronic keying protection mode that requires the physical module and
the module configured in the software to match identically, according to
vendor, catalog number, major revision and minor revision.
factory wiring 1) Wiring completed before the product was shipped from the factory in
which it was built. 2) Contrasted with field wiring (
).
field side Interface between user field-wiring and I/O module.
field wiring 1) Wiring connected by the user after the user receives the product. 2)
Contrasted with factory wiring (
hysteresis 1) The effect of residual magnetism whereby the magnetization of a ferrous
substance lags the magnetizing force because of molecular friction. 2) The
property of magnetic material that causes the magnetic induction for a given
magnetizing force to depend upon the previous conditions of magnetization.
3) A form of nonlinearity in which the response of a circuit to a particular set
of input conditions depends not only on the instantaneous values of those
conditions, but also on the immediate past of the input and output signals.
inhibit A ControlLogix process that allows you to configure an I/O module but
prevent it from communicating with the owner controller. In this case, the
controller does not establish a connection.
input See sensor (
page 121
).
intelligent I/O module 1) An I/O module that provides some on-board processing of input values to
control some output values without going through the data table for control
by the ladder logic. An intelligent I/O module may have digital I/O circuits,
analog I/O circuits, or both. 2) Contrasted with direct I/O module
(