Rockwell Automation 1771-QB Linear Pos. - Manual (Page 173)

Glossary of Terms & Abbreviations
Appendix A
AĆ4
LS: Least significant (word, byte, or bit).
mA: Milliamperes, a unit of measurement for electric current.
Memory: A group of circuit elements that can store data.
Millisecond (ms): One thousandth of a second.
Module: A unit of a larger assembly.
Motion Block: A block containing motion segments and, optionally, a
programmable I/O configuration word.
Motion Segment: A movement profile, trigger conditions, and programmable
output options that provide an advanced axis motion description.
MS: Most significant (word, byte, or bit).
Noise: An extraneous signal in an electrical circuit capable of interfering with
the desired signal.
Open Loop: A signal path without feedback.
Overshoot: The amount that a controlled variable exceeds the desired value
after a change of input.
PID: See Proportional, Integral, and Derivative control.
PLC: Programmable Logic Controller. An A-B device that you can program to
control and monitor modules in a process control system.
PLC Programming: Storing programs and ladder logic diagrams in the PLC
data table.
Proportional Control: The component that causes an output signal to change
as a direct ratio of the error signal variation.
RAM: Random access memory.
Read: To acquire data from a source, as in a block transfer of data from an I/O
module to the PLC data table.
Read Operation: A PLC request for module status information. This may be in
the form of a status block or a status monitor byte.
Register: A memory word or area used for temporary storage of data from an
intelligent I/O module to the PLC data table.
Repeatability: The ability to return to the same linear measurement along the
same axis.