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Glossary – Rockwell Automation 1761 MicroLogix 1000 Programmable Controllers User Manual

Page 399

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Glossary

G–1

Glossary

The following terms are used throughout this manual. Refer to the Allen-Bradley
Industrial Automation Glossary
, Publication Number AG-7.1, for a complete guide
to Allen-Bradley technical terms.

address: A character string that uniquely identifies a memory location. For
example, I:1/0 is the memory address for the data located in the Input file location
word1, bit 0.

AIC+ Advanced Interface Converter: a device that provides a communication
link between various networked devices. (Catalog Number 1761-NET-AIC.)

application: 1) A machine or process monitored and controlled by a controller.
2) The use of computer- or processor-based routines for specific purposes.

backup data: Data downloaded with the program.

baud rate: The speed of communication between devices on a network. All
devices must communicate at the same baud rate.

bit: The smallest storage location in memory that contains either a 1 (ON) or a 0
(OFF).

block diagrams: A schematic drawing.

Boolean operators: Logical operators such as AND, OR, NAND, NOR, NOT, and
Exclusive-OR that can be used singularly or in combination to form logic statements
or circuits. Can have an output response be true or false.

branch: A parallel logic path within a rung of a ladder program.

channel: Refers to the analog signals available on the controller’s terminal block.
Each channel is configured for connection to a voltage or current source input
device, and has its own data and diagnostic status words.

communication scan: A part of the controller’s operating cycle. Communication
with other devices, such as software running on a personal computer, takes place.

controller: A device, such as a programmable controller, used to monitor input
devices and control output devices.

controller overhead: An internal portion of the operating cycle used for
housekeeping and set-up purposes.