Industrial automation glossary

An encoder that reports a unique shaft or axis position within its measurement range, allowing a controller to recover position after startup without first counting movement from an arbitrary reference. Single-turn and multi-turn implementations differ in how much rotational history they retain.

An input channel that converts a continuously varying electrical signal into a value a controller can process. Common applications include pressure, temperature, speed, and position measurement; wiring, scaling, isolation, and signal range must match the connected transmitter.

An output channel that represents a commanded value as a continuously varying electrical signal. It is commonly used for speed references, valve commands, and instrument setpoints, with signal type, load, isolation, and scaling checked during integration.

An alternating-current motor whose rotor speed differs from the rotating magnetic field produced by the stator. Often called an induction motor, it can be operated directly from the supply or controlled by a suitable variable frequency drive.

A structured list of components, quantities, identifiers, and supporting notes required to build or maintain a machine or system. An engineering BOM may also record approved candidates, lifecycle status, documentation requirements, and items requiring review before quotation.

An external resistor used by some motor drives to dissipate regenerative energy when a motor decelerates or an overhauling load drives the motor. Selection depends on drive compatibility, energy, duty cycle, resistance, thermal conditions, and protective wiring.

A differential serial communication network used in vehicles, machines, and embedded control systems. CAN defines message arbitration and error handling at lower layers, while application protocols such as CANopen define device behavior, objects, and network management.

An application-layer protocol built on CAN for distributed automation devices. It defines device profiles, an object dictionary, process data, service data, and network management; compatibility still depends on matching profiles, communication settings, object mappings, and device functions.

A control method that measures the actual process or motion state, compares it with a target, and adjusts the command from the resulting error. Performance depends on sensor quality, controller tuning, actuator response, mechanics, and disturbances.

An IEC 61131-3-oriented engineering environment and runtime ecosystem used to develop controller applications. Projects can include logic, motion, fieldbus configuration, visualization, and diagnostics, but portability between controller vendors depends on libraries, hardware mappings, runtime features, and licenses.

The controlled process of checking an installed system before operational handover. Typical work includes verifying wiring, I/O, parameters, interlocks, communications, motion direction, alarms, safety interfaces, and documented acceptance criteria under the agreed project scope.

An engineering comparison between an existing part number and one or more candidate replacements. It considers function, electrical ratings, interfaces, mechanics, software, safety, environment, documentation, and lifecycle; every cross-brand candidate remains subject to engineering review.

Controller channels that represent discrete states rather than continuously varying values. Digital inputs receive states from switches or sensors, while digital outputs command devices such as relays and indicators; voltage, current, logic convention, isolation, and wiring type must align.

Input and output modules installed away from the main controller and connected through an industrial network. This architecture can reduce field wiring and localize connections, but bus type, update behavior, diagnostics, power segmentation, and failure response require system-level review.

The relationship between operating time, rest time, load, and repetition for a component or machine function. It affects thermal loading and sizing of motors, drives, resistors, brakes, and power supplies, so peak demand alone is not sufficient.

The ability of equipment to operate acceptably in its electromagnetic environment without causing unacceptable interference to other equipment. Practical EMC work includes cable separation, shielding, grounding, filtering, enclosure design, and installation practices appropriate to the site.

A manually initiated safety function intended to stop or reduce a hazardous situation as quickly as the machine design permits. Its devices, control architecture, reset behavior, and stopping category must be determined by the machine risk assessment.

A sensor that converts mechanical position or motion into an electrical or digital signal for control and monitoring. Selection considers measurement principle, resolution, accuracy, interface, mounting, environmental exposure, speed, and whether position must survive power loss.

A lifecycle status indicating that a manufacturer plans to stop or has stopped producing a product. EOL review covers last-time-buy decisions, installed-base support, repair strategy, software dependencies, documentation, spares, and candidate replacement planning.

An industrial Ethernet fieldbus designed for cyclic communication between a controller and distributed devices, including drives and I/O. Integration depends on device profiles, process-data mapping, timing configuration, topology, diagnostics, and support in the selected controller and engineering tools.

An industrial communication protocol that carries the Common Industrial Protocol over standard Ethernet technologies. Device interoperability depends on supported object models, connection types, data assemblies, timing, configuration files, network design, and the scanner or adapter roles implemented.

A digital communication system connecting controllers with field devices such as remote I/O, drives, sensors, and valves. Each fieldbus defines physical, data-link, and application behavior; integration requires matching interfaces, device profiles, timing, topology, and diagnostics.

A graphical programming language in which connected function blocks represent logic, signal processing, and control behavior. It is commonly used for reusable control functions, but project portability depends on supported blocks, libraries, data types, and controller-specific extensions.

The part of overall safety that depends on a control system responding correctly to detected hazards or faults. It begins with risk assessment and includes safety functions, architecture, diagnostics, verification, validation, documentation, and maintenance responsibilities.

A device or software function that connects networks, interfaces, or systems with different communication requirements. A gateway may route, encapsulate, or translate data, but successful integration depends on the application protocol, data model, timing, diagnostics, and failure behavior.

The intentional connection of equipment, shields, circuits, or enclosures to a reference or protective conductor. Correct grounding supports personnel protection, fault-current paths, signal integrity, and electromagnetic compatibility; the arrangement must follow the machine design and applicable site rules.

An operator-facing interface used to display machine status, alarms, trends, and controls. HMI integration requires more than matching screen size: communications drivers, tag mapping, user workflows, permissions, project files, mounting, and environmental conditions must also be reviewed.

The documented assignment between physical or networked input and output points and the variables used by control software. During retrofit work, mapping verifies signal type, address, polarity, scaling, terminal location, fail state, and the associated logic.

An industrial control programming standard that defines commonly used programming languages and software concepts for programmable controllers. Support varies by platform, and a project may still depend on vendor-specific libraries, task models, hardware configuration, motion functions, and runtime behavior.

An encoder that produces pulses as position changes, allowing a controller to calculate relative movement and speed. It normally requires a reference procedure after power-up if absolute position is needed; signal type, resolution, wiring, and counting capability must match.

The use of connected sensing, control, computing, and data services in industrial operations. An IIoT architecture may link machines with edge systems and enterprise applications, while addressing protocol translation, cybersecurity, ownership, latency, availability, and maintenance.

Ethernet-based communication adapted for industrial control, monitoring, and device integration. The term covers multiple protocols and network designs; suitability depends on real-time behavior, topology, redundancy, environmental hardware, traffic management, diagnostics, and cybersecurity requirements.

A network switch designed for machine or plant environments and used to connect industrial Ethernet devices. Managed features may include segmentation, redundancy, diagnostics, and traffic controls; port media, power, temperature, mounting, and protocol support must be checked per model.

A classification describing an enclosure’s stated protection against access, solid objects, and water under defined test conditions. It does not by itself establish corrosion resistance, chemical compatibility, outdoor suitability, or protection after installation, cabling, or enclosure modification.

A graphical controller programming language modeled on relay logic, using contacts, coils, and function elements arranged in networks. It is useful for discrete control and troubleshooting, but migration still requires review of instructions, scan behavior, addressing, data types, and hardware dependencies.

The engineering discipline of reducing machinery risks through inherently safe design, guards, procedures, and safety-related control functions. Component ratings alone do not establish machine compliance; the complete safety concept must be assessed, implemented, verified, and maintained by responsible parties.

A software layer that coordinates and records manufacturing execution between control systems and business planning systems. Functions may include work instructions, production tracking, quality records, genealogy, and performance data, with interfaces defined for each plant architecture.

A Modbus communication format commonly carried over serial links. Devices exchange register and coil data using addressed request-and-response messages with error checking; integration requires aligned serial settings, node addresses, register maps, data types, byte order, and timing.

A Modbus communication format carried over TCP/IP networks. It preserves the Modbus data model while using Ethernet networking; integration requires correct addressing, register maps, data representation, connection handling, network segmentation, diagnostics, and access controls.

A controller specialized for coordinated position, velocity, and torque control of machine axes. Its application may include trajectory generation, interpolation, camming, gearing, and synchronization, with drive interfaces, feedback, cycle behavior, mechanics, and safety reviewed together.

A publish-and-subscribe messaging protocol often used to exchange telemetry and events between edge systems and applications. Industrial use requires a defined topic structure, payload model, broker architecture, quality-of-service strategy, authentication, encryption, store-and-forward behavior, and data ownership.

An industrial interoperability framework that combines communication services with structured information models. It can expose data, events, methods, and relationships across platforms; deployment requires compatible profiles, namespace design, security configuration, certificate management, performance planning, and governance.

A performance level designation used in the evaluation of safety-related control functions. It is not a feature label that can be transferred between components; the complete function, architecture, diagnostics, reliability data, verification, and validation determine the achieved level.

A sensor that uses emitted light and a receiver to detect an object, contrast, distance condition, or interruption of a beam. Selection considers sensing method, target properties, background, alignment, range, response, contamination, output type, and mounting.

A feedback-control algorithm combining proportional, integral, and derivative actions to regulate a measured variable toward a setpoint. Effective use depends on process dynamics, tuning, sampling, actuator limits, noise, filtering, mode changes, and protection against integral windup.

An industrial controller designed to execute machine or process logic while interfacing with field inputs, outputs, and networks. Selection considers program scope, I/O, scan behavior, memory, communications, environmental requirements, lifecycle, and the engineering tools needed to maintain it.

A method of supplying electrical power and Ethernet data over compatible network cabling to supported devices. System design must align source and load standards, available power, cable length and quality, temperature, grounding, redundancy, and behavior during faults or startup.

An industrial Ethernet protocol used for communication between controllers and automation devices. A migration involving PROFINET must review controller roles, device descriptions, cyclic data, diagnostics, timing, topology, safety functions, and whether existing devices require retention, replacement, or a gateway.

A gateway function that translates between different application protocols or data models rather than merely forwarding packets. Engineering work includes mapping addresses and objects, converting data types, handling update rates and exceptions, defining failure states, and exposing diagnostics.

A sensor that detects the presence or approach of a target without mechanical contact. Inductive, capacitive, magnetic, and other methods respond to different materials and conditions, so range, target, mounting, environment, output circuit, and switching behavior must be checked.

A sequence of electrical pulses used to represent commanded motion, speed, position increments, or timing. Controller and drive integration requires compatible voltage, signal format, direction convention, maximum rate, isolation, cabling, and behavior during enable, stop, and faults.

An electromechanical rotary sensor that provides analog signals related to shaft angle and is often used for motor feedback. Integration requires a compatible excitation and decoding interface, correct wiring and transformation ratio, mechanical alignment, shielding, and calibration.

The modification of an existing machine or control system to replace, add, or reorganize equipment while preserving required functions. A retrofit review covers interfaces, software, wiring, mechanics, safety, documentation, downtime constraints, lifecycle risk, and commissioning.

A drive safety function that prevents torque-producing energy from being applied to a motor when activated. It does not necessarily isolate electrical power or stop all motion; its use must follow the machine risk assessment and verified safety architecture.

A discrete level used to express the required or achieved risk reduction of a safety function within a defined functional-safety framework. It applies to the complete safety function, not merely a component label, and requires appropriate design, evidence, verification, and validation.

A supervisory system used to monitor and control distributed industrial processes through data acquisition, visualization, alarms, trends, and operator commands. Its architecture typically interfaces with controllers and networks while addressing permissions, history, availability, cybersecurity, and operational procedures.

An electronic controller that regulates current, torque, speed, or position for a matched motor using command and feedback signals. Selection and tuning depend on motor data, load mechanics, feedback interface, control mode, network, braking, safety functions, and duty cycle.

A motor designed for controlled motion when paired with a compatible drive and feedback system. Correct sizing considers continuous and peak torque, speed, inertia, thermal conditions, duty cycle, brake needs, mechanics, encoder type, and environmental requirements.

A text-based industrial controller programming language with expressions, variables, conditions, loops, and functions. It suits algorithms and data handling, but project migration still requires review of libraries, task timing, data types, hardware access, motion functions, and vendor extensions.

An electronic drive that controls an alternating-current motor by adjusting its output voltage and frequency. Selection requires the motor nameplate, supply, load profile, control mode, braking, environment, interfaces, protection, and application constraints to be reviewed together.