Rockwell Automation 1762-Lxxxx MicroLogix 1200 Programmable Controllers - Manual (Page 157)

Publication 1762-UM001G-EN-P - March 2011
Glossary 5
low byte
Bits 0 to 7 of a word.
logic
A process of solving complex problems through the repeated use of simple
functions that can be either true or false. General term for digital circuits and
programmed instructions to perform required decision making and
computational functions.
Master Control Relay (MCR)
A mandatory hard-wired relay that can be de-energized by any
series-connected emergency stop switch. Whenever the MCR is de-energized,
its contacts open to de-energize all application I/O devices.
mnemonic
A simple and easy to remember term that is used to represent a complex or
lengthy set of information.
modem
Modulator/demodulator. Equipment that connects data terminal equipment
to a communication line.
modes
Selected methods of operation. Example: run, test, or program.
negative logic
The use of binary logic in such a way that “0” represents the voltage level
normally associated with logic 1 (for example, 0 = +5V, 1 = 0V). Positive is
more conventional (for example, 1 = +5V, 0 = 0V).
network
A series of stations (nodes) connected by some type of communication
medium. A network may be made up of a single link or multiple links.
nominal input current
The current at nominal input voltage.
normally closed
Contacts on a relay or switch that are closed when the relay is de-energized or
the switch is deactivated; they are open when the relay is energized or the