Rockwell Automation 1772-LS_LSP,D17726.8.6 PROG/OPER MANUAL-MINI PLC-2/05 - Manual (Page 248)

Glossary
Appendix B
BĆ12
LSD
See Least Significant Digit.
Malfunction
Any incorrect function within electronic, electrical, or mechanical hardware.
See Fault.
Manipulation
The process of controlling and monitoring data table bits, bytes, or words by
means of the user program to vary application functions.
Masking
A means of selectively screening out data. It allows unused bits in a specific
instruction to be used independently.
Master
A device used to control secondary devices.
Master Control Relay (MCR)
A mandatory hardwired relay that can be de-energized by any series-connected
emergency stop switch. Whenever the master control relay is de-energized, its
contacts open to de-energize all application I/O devices.
Master Control Reset (MCR)
See MCR Zones
Master File
A file of data containing the history or current status of a factor or entity of
interest to an organization. A master file must be updated periodically to
maintain its usefulness.
MCR Zones
User program areas where all non-retentive outputs can be turned off
simultaneously. Each MCR zone must be delimited and controlled by MCR
fence codes (MCR instructions).
Memory
A group of circuit elements that can store data.
Memory Map
A diagram showing a system’s memory addresses and what programs and data
are assigned to each section of memory.
MOS
Metal Oxide Semiconductor. A semiconductor device in which an electric field
controls the conductance of a channel under a metal electrode called a gate.
Mode
A selected method of operation. Example: run/program, remote test, or
remote program.