Industrial Automation and Control Technology Flashcards

Vocabulary-style flashcards covering basic automation elements, open and closed-loop control systems, Boolean logic, and PLC architecture and programming.

Automation

The technology by which a process or procedure is accomplished without human assistance.

Basic elements of an automated system

The three components required for automation: (1) Power, (2) Program of instructions, and (3) Control system.

Power

The element used to drive the process itself, load/unload work units, transport between operations, and operate the controller and actuate signals.

Program of Instructions

A set of commands that specify the sequence of steps in the work cycle and the details of each step.

Control System

An interconnection of components connected in a manner to command, direct, or regulate itself or another system.

Closed-loop (feedback) control system

A system where the output variable is compared with an input parameter, and any difference is used to drive the output into agreement with the input.

Open-loop control system

A system that operates without a feedback loop, which is simpler and less expensive but risks the actuator not having the intended effect.

Time-based control

A type of open-loop control system exemplified by a washing machine timer or a traffic light system.

Boolean Algebra

A mathematical system used to represent logical relationships using values $1$ (TRUE/ON) and $0$ (FALSE/OFF).

AND Operation (Conjunction)

A logic operation where the output is $1$ only if all inputs are $1$; in a PLC, this is equivalent to contacts in Series.

OR Operation (Disjunction)

A logic operation where the output is $1$ if at least one input is $1$; in a PLC, this is equivalent to contacts in Parallel.

NOT Operation (Inversion)

A logic operation where the output is the opposite of the input, represented in a PLC by a Normally Closed (NC) contact.

Programmable Logic Controller (PLC)

A microcomputer-based controller that uses stored instructions in programmable memory to implement logic, sequencing, timing, and counting functions.

Processor (PLC Component)

The part of the PLC architecture that executes logic and sequencing functions by operating on inputs to determine output signals.

Input/output module

Components in PLC architecture that provide the connections to the process.

Power supply (PLC)

A unit that converts $120\text{ V (ac)}$ to dc voltages of $\pm 5\text{ V}$ compatible with process equipment.

Scan time

The time required to perform the three steps of the PLC operating cycle (input scan, program scan, and output scan), typically between $1$ and $25\text{ msec}$.

Ladder logic diagrams

The most widely used graphical PLC programming language, where logic elements are displayed along horizontal rungs connected to vertical rails.

Contacts

Logical inputs in ladder logic, such as limit switches or photo-detectors.

Loads

Outputs in ladder logic, such as motors, lights, alarms, or solenoids.