| Term | Definition |
|---|---|
| 0–10 V signal | An analog signal range in which information is represented by voltage between zero and ten volts. |
| 1P2W-1CT metering | Single-phase, two-wire measurement arrangement using one current transformer. |
| 1P3W-2CT metering | Single-phase, three-wire metering arrangement using two current transformers. |
| 3P3W-2CT metering | Three-phase, three-wire measurement arrangement using two current transformers. |
| 3P3W-3CT metering | Three-phase, three-wire measurement arrangement using three current transformers. |
| 3P4W-3CT metering | Three-phase, four-wire measurement arrangement using three current transformers. |
| 4–20 mA signal | An analog signal range in which information is represented by current between 4 and 20 milliamps. |
| 100BASE-FX | 100 Mbit/s Ethernet physical interface using optical fiber. |
| 100BASE-TX | 100 Mbit/s Ethernet physical interface using twisted-pair copper. |
| 333 mV-output current transformer | Current transformer providing a specified low-voltage measurement output. |
| 1000BASE-LX | Gigabit fiber Ethernet interface associated with long-wavelength optical links. |
| 1000BASE-SX | Gigabit fiber Ethernet interface commonly associated with short-wavelength multimode links. |
| 1000BASE-T | Gigabit Ethernet physical interface using twisted-pair copper. |
| Access point name (APN) | Provider-specified cellular access configuration used to establish a mobile data connection. |
| AC coupling | Signal coupling that passes changing components while blocking the steady DC component. |
| Acquisition buffer clear | Operation discarding stored acquisition-buffer contents. |
| Acquisition buffer data count | Number of acquired values currently reported in the software buffer. |
| Acquisition data-ready event | Notification indicating a configured amount of acquired data is available. |
| Acquisition event callback | Application function invoked when a configured acquisition event occurs. |
| Ammonia (NH3) | Gas measured as an environmental or process-monitoring parameter. |
| Analog-to-digital converter (ADC) | A circuit that converts an analog signal into a numerical representation. |
| Analog bandwidth | The frequency range over which an analog signal path operates within its specified response. |
| Analog input (AI) | An input channel that measures a continuously varying signal, such as voltage or current. |
| Analog output (AO) | An output channel that produces a variable signal to command equipment. |
| Analog pattern generator | An output function that produces a programmed sequence of analog waveform values. |
| Analog trigger | An acquisition trigger generated when an analog signal meets a configured condition. |
| Apparent energy | Time accumulation of apparent power, commonly reported in kVAh. |
| Auto-negotiation | Automatic selection of compatible Ethernet link operating settings between connected devices. |
| Auto MDI/MDI-X | Automatic adjustment for straight-through or crossover Ethernet cable connections. |
| BACnet | A communication protocol designed for building automation and control networks. |
| BACnet Analog Input object | BACnet object representing an analog input measurement. |
| BACnet Analog Output object | BACnet object representing an analog output point. |
| BACnet Analog Value object | BACnet object representing an analog value rather than a physical input or output. |
| BACnet Binary Input object | BACnet object representing a two-state input point. |
| BACnet Binary Output object | BACnet object representing a two-state output point. |
| BACnet Binary Value object | BACnet object representing an internal two-state value. |
| BACnet Device object | BACnet object representing the device itself rather than an individual I/O point. |
| BACnet MS/TP | A BACnet data-link option using token passing over an RS-485 network. |
| BACnet MS/TP station number | Local address identifying a station on an MS/TP segment. |
| BACnet Multi-state Input object | BACnet object representing an input with several discrete states. |
| BACnet Multi-state Output object | BACnet object representing an output with several discrete states. |
| BACnet Multi-state Value object | BACnet object representing an internal value with several discrete states. |
| BACnet Out_Of_Service property | Object property indicating whether its normal physical-service relationship is taken out of service. |
| BACnet Present_Value property | Object property carrying its current represented value. |
| BACnet ReadProperty service | Request retrieving a selected BACnet object property. |
| BACnet write priority | Priority assigned to a write command, with lower numbers taking precedence. |
| BACnet WriteProperty service | Request changing a selected writable BACnet object property. |
| Baud rate | The number of signaling symbols transmitted each second on a communication link. |
| Bipolar signal range | A signal range that includes both positive and negative values around zero. |
| Buffer overflow | A condition where incoming samples exceed the available acquisition buffer capacity. |
| Burst PWM mode | A mode that produces a configured number of PWM pulses. |
| Byte-order swap | Rearranging bytes in a multi-byte value so communicating devices interpret the value consistently. |
| CAN acceptance code | Configured identifier pattern used by the receive acceptance filter. |
| CAN acceptance mask | Bit mask selecting identifier bits compared by the acceptance filter. |
| CAN bit-rate prescaler (BRP) | Clock-divider parameter used to derive CAN bit timing. |
| CAN bus (Controller Area Network) | A shared serial network that allows industrial controllers and devices to exchange prioritized messages. |
| CAN bus-on state | Controller condition permitting participation in bus activity. |
| CAN bus bridge | Device linking CAN networks while handling their communication segments independently. |
| CAN bus repeater | Device restoring CAN signal quality between physically coupled network segments. |
| CAN converter pair-connection mode | Mode transporting serial data inside CAN messages using a configured identifier. |
| CAN data-overrun status | Controller indication that a received message was lost through overrun. |
| CAN data length code (DLC) | Encoded field indicating the number of data bytes in a CAN frame. |
| CAN error warning limit | Threshold used to flag excessive controller error counts. |
| CAN extended frame | CAN frame using a 29-bit identifier. |
| CAN FD (CAN with Flexible Data Rate) | An extension of Classical CAN supporting larger data payloads and optional faster data-phase transmission. |
| CAN FD bit-rate switching | Transition from nominal arbitration timing to a different data-phase bit rate. |
| CAN FD data bit rate | Bit rate used for the CAN FD data phase. |
| CAN FD error state indicator (ESI) | CAN FD field indicating the transmitting node's active or passive error state. |
| CAN FD format flag (FDF) | Message-format indicator distinguishing CAN FD frames from Classical CAN frames. |
| CAN FD nominal bit rate | Bit rate used during CAN FD arbitration. |
| CAN listen-only mode | Receive-only mode withholding transmitted CAN signals, including acknowledgments and error frames. |
| CANopen | A CAN-based application protocol used for configurable industrial device networks. |
| CANopen communication object identifier (COB-ID) | Identifier assigned to a CANopen communication object. |
| CANopen error register | Object 0x1001 holding the device's summarized error condition. |
| CANopen identity object | Object 0x1018 containing vendor, product, revision, and serial identifiers. |
| CANopen Initialising state | Startup state in which a node initializes before normal protocol operation. |
| CANopen object dictionary | A structured collection of a CANopen device's communication parameters and application data. |
| CANopen object index | Main numerical address of an object-dictionary entry. |
| CANopen object subindex | Numerical selector for an element within an object-dictionary entry. |
| CANopen Operational state | CANopen state permitting normal PDO-based process-data exchange. |
| CANopen PDO event timer | Timer parameter controlling periodic transmission of a transmit PDO. |
| CANopen PDO inhibit time | Parameter limiting how frequently a transmit PDO may be sent. |
| CANopen PDO transmission type | Parameter selecting the transmission behavior of a PDO. |
| CANopen Pre-Operational state | CANopen state allowing configuration communication while normal PDO exchange is inactive. |
| CANopen receive PDO (RxPDO) | Process data object received by a CANopen node. |
| CANopen SDO client | Node role initiating object-dictionary access through SDO communication. |
| CANopen SDO server | Node role handling SDO access to its object dictionary. |
| CANopen Stopped state | CANopen state restricting normal application communication while network management remains available. |
| CANopen time stamp object | Communication object distributing time information within a CANopen network. |
| CANopen transmit PDO (TxPDO) | Process data object transmitted by a CANopen node. |
| CAN phase segment 1 | Timing segment before the sample point used in bit synchronization. |
| CAN phase segment 2 | Timing segment after the sample point used in bit synchronization. |
| CAN propagation segment | Part of a CAN bit period allocated to signal-propagation delay. |
| CAN receive-buffer status | Controller indication showing whether received messages are available. |
| CAN receive error counter (REC) | Controller counter tracking receive-side communication errors. |
| CAN remote frame | Classical CAN frame requesting data rather than carrying a data payload. |
| CAN sample point | Position within the bit period where the receiver samples the signal. |
| CAN standard frame | CAN frame using an 11-bit identifier. |
| CAN synchronization jump width (SJW) | Limit on timing adjustment allowed during CAN resynchronization. |
| CAN time quantum (TQ) | Timing subdivision used to construct a CAN bit period. |
| CAN transmit-buffer status | Controller indication showing whether transmit-buffer space is available. |
| CAN transmit error counter (TEC) | Controller counter tracking transmit-side communication errors. |
| CAN triple sampling | Controller option sampling a bit three times rather than once. |
| Cellular network registration | Status indicating whether a modem has joined its mobile network. |
| Certificate Common Name (CN) | Certificate identity field containing the configured server name. |
| Channel-to-channel isolation | Electrical separation between individual measurement channels. |
| CIP (Common Industrial Protocol) | The object-based industrial communication framework used by EtherNet/IP. |
| CIP attribute identifier | Number selecting a property within a CIP object. |
| CIP class identifier | Number selecting an object class in the CIP object model. |
| CIP Connection Manager Object | Object managing creation of communication connections. |
| CIP Ethernet Link Object | Object representing Ethernet-link-specific configuration or status information. |
| CIP Identity Object | Object exposing device identification and revision information. |
| CIP instance identifier | Number selecting a particular instance of a CIP object class. |
| CIP Message Router Object | Object directing explicit requests to the specified target object. |
| Clear to Send (CTS) | An RS-232 control signal indicating permission for the peer to transmit. |
| Coil | A readable and writable single-bit Modbus data location. |
| Cold-junction compensation (CJC) | Correction for the reference-junction temperature when converting thermocouple voltage into temperature. |
| Communication watchdog | A timer that detects lost host communication and triggers a configured response. |
| Conducted emissions | Electromagnetic disturbances leaving equipment through its connected conductors. |
| Conducted RF immunity | Ability assessed against radio-frequency disturbances introduced through connected conductors. |
| Continuous capture | Acquiring a continuing stream of measurements rather than just one reading. |
| Continuous PWM mode | A mode that produces repeated PWM pulses until output is stopped. |
| Control timer | A timing function used to delay or schedule a logic action. |
| Counter electromotive force | A generated voltage opposing a change in current, including the transient produced when an inductive load is switched. |
| Counter input | An input that counts incoming signal pulses or transitions. |
| CT aperture | Opening in a current transformer through which the measured conductor passes. |
| CT primary-current rating | Primary current assigned to a CT for its specified output rating. |
| Current load resistance | The connected resistance that a current output must drive within its specified operating limit. |
| Current transformer (CT) | A measurement transformer that produces an output related to current in a primary conductor. |
| Cyclic data transfer | Transmission of process data repeatedly at configured intervals. |
| Daisy-chain topology | A network arrangement that connects devices sequentially through their communication ports. |
| DALI address allocation | Commissioning operation assigning device addresses on a DALI bus. |
| DALI broadcast address | Address pattern selecting all devices on a DALI bus. |
| DALI bus power supply | Power source supplying the DALI communication bus. |
| DALI device address | Address selecting an individual device on a DALI bus. |
| DALI group address | Address selecting a group of DALI devices. |
| DALI presence map | Bit map indicating which DALI device addresses are present. |
| DALI select bit | Address-byte bit distinguishing lamp-power data from a command code. |
| DAQ card identifier | Hardware-selectable identifier used to distinguish installed acquisition cards in software. |
| Data acquisition (DAQ) | Collecting measurements from connected inputs for monitoring, recording, or analysis. |
| Data carrier detect (DCD) | RS-232 status signal reporting carrier detection. |
| Data communication equipment (DCE) | Serial endpoint role exemplified by a modem in RS-232 wiring diagrams. |
| Data mapping | Assigning data in one protocol or address space to corresponding locations in another. |
| Data set ready (DSR) | RS-232 control signal indicating communications-equipment readiness. |
| Data terminal equipment (DTE) | Serial endpoint role exemplified by a computer in RS-232 wiring diagrams. |
| Data terminal ready (DTR) | RS-232 control signal indicating terminal readiness. |
| DCON | An ICP DAS command protocol used to configure devices and read or control their I/O. |
| DCON ASCII checksum | Optional two-character check value derived from the message's ASCII-code sum. |
| DCON command terminator | Carriage-return character ending a DCON command string. |
| Default gateway | The router used to reach destinations outside a device's local subnet. |
| Denial-of-service attack (DoS) | Attack disrupting service through abnormal or excessive requests or traffic. |
| DeviceNet | A CAN-based industrial network that connects controllers with field devices such as sensors and actuators. |
| DeviceNet bit-strobe command | Master command used to solicit bit-strobe I/O responses. |
| DeviceNet connection ID | CAN identifier identifying a DeviceNet communication connection. |
| DeviceNet Connection Object | Object representing communication connection endpoints and their parameters. |
| DeviceNet consumed connection ID | Identifier associated with messages received by a connection endpoint. |
| DeviceNet consumed connection size | Size of the data a connection endpoint receives. |
| DeviceNet duplicate MAC ID check | Message exchange checking whether a node address conflicts with another device. |
| DeviceNet expected packet rate | Connection timing parameter specifying the expected interval for packet exchange. |
| DeviceNet MAC ID | Node identifier selecting a DeviceNet subscriber, distinct from an Ethernet MAC address. |
| DeviceNet polled I/O connection | I/O exchange where a master polls a specific slave and receives its response. |
| DeviceNet predefined master/slave connection set | Standardized connection arrangement for master/slave exchanges on DeviceNet. |
| DeviceNet produced connection ID | Identifier associated with messages sent by a connection endpoint. |
| DeviceNet produced connection size | Size of the data a connection endpoint sends. |
| DeviceNet watchdog timeout action | Connection setting defining the response to a watchdog timeout. |
| DHCP (Dynamic Host Configuration Protocol) | A network protocol that automatically supplies address configuration to connected devices. |
| Differential input | An analog input measured as the voltage difference between two input terminals. |
| Digital-to-analog converter (DAC) | A circuit that converts a numerical value into an analog output signal. |
| Digital Addressable Lighting Interface (DALI) | Standardized communication interface for lighting control. |
| Digital input (DI) | An input channel that detects an on/off signal. |
| Digital output (DO) | An output channel that switches a signal on or off. |
| Digital pattern generator | An output function that produces a programmed sequence of digital states. |
| Discrete input | A read-only single-bit Modbus location representing an input state. |
| Distributed Clocks (DC) | EtherCAT clock synchronization that aligns device timing to a shared reference. |
| Distributed denial-of-service attack (DDoS) | Service-disruption attack originating from multiple distributed sources. |
| DNP3 (Distributed Network Protocol) | A telemetry protocol used to exchange process data and control commands in SCADA systems. |
| DNP3 analog input point | DNP3 point representing a numeric input measurement. |
| DNP3 analog output point | DNP3 point representing a numeric output value or command. |
| DNP3 binary input point | DNP3 point representing a two-state input value. |
| DNP3 binary output point | DNP3 point representing a two-state output value or control. |
| DNP3 master station | DNP3 communication role accessing data and controls in outstations. |
| DNP3 object group | Group number identifying a DNP3 data-object category. |
| DNP3 object variation | Selector identifying a particular representation within a DNP3 object group. |
| DNP3 outstation | Remote DNP3 endpoint providing process data and accepting supported controls. |
| Dry contact | An unpowered switch contact whose open or closed state is detected by an input circuit. |
| Dual-SIM failover | Switching between installed SIMs when cellular reconnection is needed. |
| Dual-slope conversion | An integrating conversion method using an input integration phase followed by a reference integration phase. |
| Dual watchdog | Arrangement combining local-module and host-communication monitoring. |
| Duty cycle | The percentage of each waveform period during which the signal is active. |
| Dynamic DNS (DDNS) | DNS updating service used to maintain a hostname for a changing network address. |
| Electrical fast transient (EFT) | Rapid electrical disturbance associated with the fast-transient immunity test category. |
| Electromechanical relay | An electrically operated switch that moves mechanical contacts to connect or disconnect a circuit. |
| Electronic control unit (ECU) | Microprocessor-based controller exchanging vehicle information over networks such as J1939. |
| Electrostatic discharge (ESD) | Discharge of accumulated static charge affecting electronic equipment or its connections. |
| Encoder CRC-error indication | Diagnostic flag reporting a failed check of received encoder data. |
| Encoder CRC inversion | Setting accounting for an encoder transmitting an inverted CRC value. |
| Encoder data-ready flag | Status indicating that encoder data preparation is complete. |
| Encoder input-cycle counter | Counter incremented for correctly read encoder process-data updates. |
| Encoder multi-turn position | Position data recording the encoder's accumulated turn count. |
| Encoder serial clock frequency | Pulse frequency governing a serial encoder's data transmission. |
| Encoder single-turn position | Position value representing location within one encoder revolution. |
| Energy Efficient Ethernet (EEE) | Ethernet mechanism reducing power use during idle network activity. |
| Engineering units | Physical units used to express measurements, such as volts, milliamps, or degrees Celsius. |
| Equivalent isotropically radiated power (EIRP) | Radiated-power specification expressed relative to an isotropic reference antenna. |
| EtherCAT | An industrial Ethernet fieldbus used for coordinated I/O and motion communication. |
| EtherCAT Calc and Copy Time | Slave timing parameter describing process-data copying and output calculation time. |
| EtherCAT Init state | Startup state allowing controller-register access without mailbox or process-data exchange. |
| EtherCAT Operational state | State permitting cyclic input and output process-data exchange. |
| EtherCAT Pre-Operational state | State permitting mailbox communication before process-data exchange becomes active. |
| EtherCAT Safe-Operational state | State updating inputs while outputs remain at configured safe values. |
| EtherCAT sync-manager watchdog | Supervision that detects missing output process data within a configured interval. |
| EtherCAT SYNC0 event | Distributed-clock timing event used to synchronize device processing. |
| EtherCAT SYNC1 event | Distributed-clock event available for synchronized slave processing. |
| EtherCAT synchronization error counter | Diagnostic counter tracking failures to meet configured synchronized communication timing. |
| Ethernet | A family of networking standards used to exchange frames across local-area networks. |
| EtherNet/IP | An industrial Ethernet protocol that exchanges control and device data through CIP objects. |
| EtherNet/IP adapter | A device that provides I/O data and services to an EtherNet/IP scanner. |
| EtherNet/IP input assembly | Collection of process data transferred from adapter to scanner. |
| EtherNet/IP scanner | A device that initiates communication with EtherNet/IP adapters. |
| Ethernet backpressure flow control | Half-duplex link flow-control method used to manage reception congestion. |
| Ethernet dual-media port | Port supporting copper or fiber interface selection. |
| Ethernet LAN bypass | Hardware forwarding path maintaining a daisy-chain connection when a module loses power. |
| Event-triggered data binding | Exchanging linked variable data between controllers when configured events occur. |
| Excitation adjustment | Adjustment of the electrical supply used to energize a connected sensor. |
| Excitation voltage | A supplied voltage used to energize a sensor or measurement bridge. |
| Explicit messaging | EtherNet/IP request-and-response communication for accessing device objects and their attributes. |
| FIFO (First In, First Out) | A data queue that returns stored samples in their arrival order. |
| Floating digital input | Input lacking a defined state when disconnected or insufficiently biased. |
| Flyback diode | A diode across a DC inductive load that limits voltage generated when current is interrupted. |
| Formaldehyde (HCHO) | Airborne chemical measured as an air-quality monitoring parameter. |
| Free Run mode | Operation where an EtherCAT device's local cycle runs independently of the master's cycle. |
| FRnet | Remote-I/O network used to exchange controller data with FRnet modules. |
| FRnet receiver address | Address identifying the receiving side of a FRnet data relationship. |
| FRnet sender address | Address identifying the sending side of a FRnet data relationship. |
| FSK (Frequency Shift Keying) | Representing digital information by switching between different signal frequencies. |
| Full-duplex communication | Communication that permits simultaneous transmission and reception. |
| Full-scale range (FSR) | The span between the lower and upper limits of a configured measurement range. |
| Function Block Diagram (FBD) | A graphical PLC language that connects functional blocks to express control operations. |
| Function code | A Modbus message field identifying the requested operation. |
| Global Positioning System (GPS) | Satellite-based system used by receivers for positioning and time information. |
| GPS acquisition time | Time required by a receiver to acquire a usable satellite solution under specified conditions. |
| GPS cold start | Receiver startup condition requiring initial satellite acquisition rather than established tracking. |
| GSD file | ASCII device-description file specifying PROFIBUS communication capabilities and configuration parameters. |
| GSDML file | An XML-based PROFINET device-description file used by engineering tools for configuration. |
| Hardware trigger | An external electrical event that starts a configured acquisition or output operation. |
| HART | A communication protocol that combines digital instrument data with an analog current signal. |
| HART burst mode | Mode where an instrument repeatedly transmits configured HART response messages. |
| HART byte count | A frame field giving the number of following bytes before the check byte; the check byte is excluded. |
| HART check byte | Trailing frame check value used to detect communication errors. |
| HART Command 1: Read Primary Variable | Command retrieving the instrument's primary variable and unit information. |
| HART Command 2: Read Current and Percent of Range | Command retrieving primary-variable current and percentage-of-range values. |
| HART Command 3: Read Dynamic Variables | Command retrieving dynamic variables, their unit codes and primary-variable current. |
| HART Command 6: Write Polling Address | Command changing a supported instrument's polling address. |
| HART Command 11: Read Identifier by Tag | Command retrieving device identity associated with a supplied instrument tag. |
| HART Command 12: Read Message | Command retrieving the instrument's stored message text. |
| HART common-practice command | Command from the HART class providing commonly used instrument functions beyond universal commands. |
| HART delimiter | Frame field identifying message direction and short or long addressing. |
| HART device-specific command | HART command providing functions particular to an instrument family. |
| HART field device status | Status byte reporting conditions such as malfunction or out-of-limit variables. |
| HART listen-only mode | Mode acquiring HART traffic without acting as the polling host. |
| HART long frame | HART message using a five-byte address incorporating device identity. |
| HART loop resistor | Loop resistance used to provide suitable conditions for HART signaling. |
| HART preamble | Leading synchronization characters transmitted before the remainder of a HART frame. |
| HART primary master | Primary host role in a HART network supporting two master roles. |
| HART response codes | Status bytes reporting communication, command, and field-device conditions. |
| HART secondary master | Additional HART host role operating alongside the primary master. |
| HART short frame | HART message using a one-byte address field. |
| HART through mode | Gateway mode allowing a host to pass HART commands to instruments. |
| HART universal command | Command from the common baseline HART command class. |
| Heartbeat | A periodic CANopen message indicating that a device remains available. |
| HMI (Human Machine Interface) | An operator interface for viewing process conditions and interacting with equipment. |
| Holding register | A readable and writable 16-bit Modbus data location. |
| HTTP (Hypertext Transfer Protocol) | An application protocol used by web browsers and device web servers to exchange requests and responses. |
| HTTPS | HTTP communication protected by a TLS-secured connection. |
| I/O isolation | Electrical separation between field-side I/O connections and other module circuitry. |
| I/O pair connection | Linking input states on one device to corresponding outputs on another. |
| I/O port address | Hardware address used for port-based peripheral access. |
| IEC 61131-3 | An international standard defining PLC programming languages and related software concepts. |
| IEC 61850 | A standard defining communication and structured information models for electrical substation automation. |
| IEC 61850 data attribute | Property contained within an IEC 61850 data object. |
| IEC 61850 data object | Named information element contained within a logical node. |
| IEC 61850 data set | Configured collection of data used for information exchange. |
| IEC 61850 logical-node prefix | Optional leading component of a logical-node instance name. |
| IEC 61850 logical device | Logical grouping within an IEC 61850 physical device's information model. |
| IEC 61850 logical node | Functional information-model element containing related data objects. |
| IEC 61850 MMXU | Logical-node class representing electrical measurement values. |
| IEC 61850 unbuffered reporting | Report-based data exchange without retained reports for later delivery. |
| IEEE 802.3af | Ethernet standard specifying the original standardized PoE power-delivery arrangement. |
| IEEE 802.3at PoE+ | PoE standard extending power capability beyond the original IEEE 802.3af level. |
| IEEE 802.3bt | PoE standard supporting higher-power Ethernet powering, including Type 4 equipment. |
| IEEE 802.3x flow control | Ethernet link flow-control mechanism for managing reception pressure. |
| IEEE 802.15.4 | Wireless specification underlying the radio networks used by ZigBee devices. |
| IEPE sensor | A piezoelectric sensor with integrated electronics powered through a constant-current interface. |
| Implicit messaging | EtherNet/IP communication used to exchange I/O data through established connections. |
| Individual channel configuration | Setting measurement parameters separately for each input channel. |
| Inductive load | A load that stores energy in a magnetic field and can produce voltage transients when switched. |
| Industrial Ethernet switch | A device that forwards Ethernet traffic among connected industrial network devices. |
| Input debouncing | Rejecting rapid contact transitions so one switch action is recognized reliably. |
| Input impedance | The electrical impedance presented by a measurement input to its signal source. |
| Input range | The configured span of signal values an analog input measures. |
| Input register | A read-only 16-bit Modbus location containing input data. |
| Instruction List (IL) | A PLC language that expresses operations as a sequence of instruction statements. |
| Integrating ADC | An analog-to-digital converter that determines a value by integrating the input over time. |
| Intelligent electronic device (IED) | Electronic protection or control device communicating in a substation system. |
| International mobile equipment identity (IMEI) | Identifier associated with the cellular modem equipment. |
| IP address | A numerical address identifying a network interface for Internet Protocol communication. |
| IP address allow-list | A configured list of source addresses permitted to connect to a device. |
| IPv4 | The Internet Protocol version using 32-bit network addresses. |
| IPv4/IPv6 dual stack | Network operation supporting both IPv4 and IPv6. |
| IPv6 | The Internet Protocol version using 128-bit network addresses. |
| ISM radio band | Radio-frequency band designated for industrial, scientific, and medical uses. |
| ISO CAN FD | Standardized CAN FD format distinguished from the earlier non-ISO format. |
| Isolated DC-to-DC converter | A power converter that electrically separates its DC input from its DC output. |
| J1939 | A CAN-based communication standard used for data exchange and diagnostics in heavy-duty vehicles and mobile equipment. |
| J1939 address claim | Network procedure through which a device claims its communication address. |
| J1939 Broadcast Announce Message (BAM) | Transport mechanism announcing a multi-packet message sent to the global destination. |
| J1939 destination address | Message address identifying the intended recipient where destination addressing applies. |
| J1939 NAME | 64-bit identity value identifying a J1939 network device. |
| J1939 parameter group number (PGN) | Number identifying a J1939 message's function and associated data. |
| J1939 PDU1 format | J1939 message format carrying a destination address. |
| J1939 PDU2 format | J1939 message format used for broadcast communication. |
| J1939 proprietary PGN | Parameter group number reserved for manufacturer-defined message content. |
| J1939 source address | Message address identifying the transmitting network node. |
| J1939 suspect parameter number (SPN) | Identifier for a defined parameter within J1939 data. |
| J1939 transport protocol | Mechanism fragmenting and reassembling messages larger than one classic CAN payload. |
| Jumbo frame | An Ethernet frame larger than the conventional standard frame size. |
| Keep-alive interval | The MQTT interval within which an idle client must send PINGREQ to maintain its connection. |
| Ladder Diagram (LD) | A graphical PLC language that represents control logic using contacts, coils, and rungs. |
| Last Will and Testament (LWT) | An MQTT message published by the broker after a client's unexpected disconnection. |
| Lead resistance compensation | Correcting a sensor reading for resistance contributed by connecting wires. |
| Limit switch | An input device used to stop motion when a travel boundary is reached. |
| Load current | The electrical current drawn by equipment connected to an output. |
| Load voltage | The voltage supplied to or switched across a connected output load. |
| LoRa | A long-range radio technology used to carry low-rate wireless data between compatible devices. |
| Low-pass input filter | Filtering that rejects short disturbances while allowing slower input-state changes to pass. |
| Lower cutoff frequency | The lower frequency boundary of a signal conditioner's specified response. |
| M-Bus application-reset subcode | Selection identifying a supported meter data group to be read. |
| M-Bus meter medium field | Metadata identifying the medium measured by a meter. |
| MAC address aging time | Retention interval for learned MAC table entries. |
| MAC learning table | Switch table associating learned MAC addresses with forwarding locations. |
| Man-in-the-middle attack | Interception of communication by an intermediary attempting to observe or alter exchanged data. |
| Management Information Base (MIB) | A structured description of the objects exposed for network management. |
| Measurement accuracy | The specified closeness of a measurement to the reference or true value under stated conditions. |
| Memory-mapped I/O (MMIO) | Peripheral access through mapped memory addresses. |
| Message signing | Adding a cryptographic signature to establish message authenticity and detect changes. |
| Meter CT ratio | Meter scaling setting relating current-transformer measurements to the monitored primary current. |
| Meter PT ratio | Meter scaling setting compensating for the connected potential transformer's voltage ratio. |
| Millivolt input | A measurement input intended for small voltage signals expressed in millivolts. |
| Minimum pulse width | The shortest input pulse duration that a device specifies it can recognize. |
| Modbus ASCII | A serial Modbus format that represents message bytes as ASCII characters. |
| Modbus client (master) | The device that initiates Modbus requests. |
| Modbus Illegal Data Address exception | Exception 0x02 indicating a requested data address is not allowable. |
| Modbus Illegal Data Value exception | Exception 0x03 indicating an unacceptable value in the request. |
| Modbus Illegal Function exception | Exception 0x01 indicating an unsupported or disallowed requested function. |
| Modbus over TLS | Modbus TCP communication protected through TLS. |
| Modbus RTU | A binary Modbus message format used over serial communication links. |
| Modbus server (slave) | The device that responds to Modbus requests. |
| Modbus TCP | Modbus communication carried over a TCP/IP network. |
| Module watchdog | Hardware watchdog monitoring a module and resetting its processor after detected failure. |
| Motion command buffer mode | Setting governing whether an incoming motion command interrupts or queues behind another. |
| MQTT | A messaging protocol that distributes published data through a broker to subscribing clients. |
| MQTT broker | The server that receives published messages and routes them to matching subscribers. |
| MQTT command topic | Topic used by an application to deliver commands to a subscribing device. |
| MQTT over TLS | MQTT communication protected by a TLS-encrypted connection. |
| MQTT periodic publish interval | Configured interval controlling scheduled publication of enabled messages. |
| MQTT PINGREQ packet | Client keep-alive request sent to the broker. |
| MQTT PINGRESP packet | Broker response to a client's keep-alive request. |
| MQTT publisher | Client role sending messages on topics to an MQTT broker. |
| MQTT QoS 0 | At-most-once message delivery level. |
| MQTT QoS 1 | At-least-once message delivery level, allowing duplicates. |
| MQTT QoS 2 | Exactly-once MQTT message delivery level within the protocol exchange. |
| MQTT subscriber | Client role receiving broker-delivered messages for subscribed topics. |
| MQTT topic configuration import/export | Transfer of saved topic settings between configuration files and a device. |
| MQTT topic prefix | Common leading string used when constructing related MQTT topic names. |
| Multi-master architecture | A network arrangement in which multiple devices can initiate communication. |
| Multicast DNS (mDNS) | Local-network hostname resolution using multicast discovery. |
| Multidrop HART | A shared HART network where multiple addressed field devices transmit process values digitally. |
| Netstat connection monitoring | Inspection of listening ports and established network connections. |
| Network management system (NMS) | Software that monitors and manages devices through network management interfaces. |
| Network port | A numerical identifier used to direct network traffic to a particular service or application. |
| NMEA 0183 | Serial data format used to exchange receiver navigation information. |
| NMEA GGA sentence | Sentence carrying position, time and fix-quality information. |
| NMEA GLL sentence | Sentence carrying geographic position, time and validity status. |
| NMEA GSA sentence | Sentence reporting receiver mode, active satellites and dilution values. |
| NMEA GSV sentence | Sentence describing satellites in view and associated signal information. |
| NMEA RMC sentence | Sentence carrying a minimum set of navigation data including time, position and speed. |
| NMEA talker identifier | Two-character sentence-header identifier indicating the reporting satellite system. |
| NMEA VTG sentence | Sentence reporting track and speed over ground. |
| Node guarding | A CANopen mechanism that checks device availability through requests and responses. |
| Non-ISO CAN FD | Earlier CAN FD format requiring compatible non-ISO communication settings. |
| Normally open contact (NO) | A contact that is open in its normal, unactuated state. |
| NTP (Network Time Protocol) | A network protocol used to synchronize device clocks. |
| Offline simulation | Testing a control program on a computer without running it on the target controller. |
| OFF voltage level | The specified input-voltage condition recognized as an inactive digital state. |
| Omnidirectional antenna | Antenna intended to provide coverage around its principal axis. |
| Online change | Updating a running control application without stopping its execution, where the controller supports it. |
| ON voltage level | The specified input-voltage condition recognized as an active digital state. |
| OPC UA (Open Platform Communications Unified Architecture) | An industrial communication framework for exchanging structured data between clients and servers. |
| OPC UA anonymous identity token | User identity token allowing session access without username credentials. |
| OPC UA endpoint | A server connection address associated with communication and security settings. |
| OPC UA message security mode | Setting determining whether messages are unsecured, signed, or signed and encrypted. |
| OPC UA None mode | Message security mode without message signing or encryption. |
| OPC UA session | An application-level interaction context established between a client and server. |
| OPC UA SignAndEncrypt mode | Message security mode applying both signatures and message encryption. |
| OPC UA subscription | A server-managed arrangement that delivers monitored data notifications to a client. |
| OPC UA trusted certificate store | Collection of accepted peer certificates used in establishing trusted communication. |
| OPC UA username identity token | User identity token carrying a username and associated credential information. |
| Open-wire detection | Identifying a disconnected or broken sensor connection. |
| Output power-on value | Preset output value applied at module startup or specified resets. |
| Overload protection | A protective function that responds when a connected load draws excessive current. |
| PAC (Programmable Automation Controller) | An automation controller combining industrial control, computing, networking, and expandable I/O. |
| Parity bit | An additional serial bit used for a basic transmission error check. |
| Particle count | Number of detected particles, often categorized into specified size bins. |
| PDO (Process Data Object) | A CANopen communication object used to exchange time-sensitive process data. |
| Photo-couple isolation | Electrical separation that transfers a signal through light rather than a direct conductive connection. |
| PID auto-tuning | Automatically determining suitable PID parameters for a connected control process. |
| PID control | Feedback control that combines proportional, integral, and derivative actions to regulate a process. |
| PID derivative gain (Kd) | A setting controlling the derivative contribution to a PID controller's output. |
| PID integral gain (Ki) | A setting controlling the integral contribution to a PID controller's output. |
| PID output limit | A configured minimum or maximum restricting the controller's output value. |
| PID proportional gain (Kp) | A setting controlling the proportional contribution to a PID controller's output. |
| PID sample time | The interval at which the PID calculation uses updated input information. |
| PLC (Programmable Logic Controller) | An industrial controller that executes programmed logic to control connected equipment. |
| PLCopen Busy output | Function-block output indicating that execution has not yet completed. |
| PLCopen CommandAborted output | Function-block output indicating interruption of the command before normal completion. |
| PLCopen Continuous Motion state | Axis state executing movement without a predefined final position. |
| PLCopen Disabled state | Axis state entered when its motion power-enable function is inactive. |
| PLCopen Discrete Motion state | Axis state executing a move to a defined target position. |
| PLCopen Done output | Function-block output indicating successful completion of the requested operation. |
| PLCopen Enable input | Level-sensitive input keeping the associated function block active while true. |
| PLCopen ErrorStop state | Axis error state preventing normal motion until the cause is handled and reset. |
| PLCopen Execute input | Edge-triggered input starting a motion-function-block operation with captured parameters. |
| PLCopen Standstill state | Axis state indicating enabled, stationary readiness for motion commands. |
| PLCopen Stopping state | Axis state used while a stop command controls deceleration and inhibits normal command progression. |
| PLCopen Valid output | Function-block output indicating that its reported output values are currently valid. |
| PM1 | Particulate-matter measurement category associated with particles up to approximately one micrometer. |
| PM2.5 | Particulate-matter measurement category associated with particles up to approximately 2.5 micrometers. |
| PM10 | Particulate-matter measurement category associated with particles up to approximately ten micrometers. |
| PoE endspan | Power sourcing equipment integrated with an Ethernet switch. |
| PoE midspan | Power-injection equipment positioned between an Ethernet switch and powered device. |
| PoE Mode A | PoE arrangement applying power through Ethernet data-pair conductors in the documented two-pair scheme. |
| PoE Mode B | PoE arrangement applying power through the other pair set in the documented two-pair scheme. |
| PoE powered device (PD) | Equipment receiving and using power delivered through Ethernet cabling. |
| PoE power schedule | Schedule automatically enabling or disabling power on selected PoE ports. |
| PoE power sourcing equipment (PSE) | Equipment supplying power to compatible devices through Ethernet cabling. |
| PoE splitter | Device separating received PoE power from Ethernet data for downstream use. |
| Point-to-point HART | A HART connection with one field device, carrying analog and digital information. |
| Polling | Software-requested reading of an input channel rather than waiting for an event notification. |
| Port-based VLAN | VLAN grouping determined by switch-port membership. |
| Port forwarding | Router mapping that directs incoming traffic to a specified internal endpoint. |
| Potential transformer (PT) | A measurement transformer that reduces voltage to a level suitable for metering equipment. |
| Power-down counter retention | Saving a pulse count to nonvolatile memory when power is lost. |
| Power-frequency magnetic-field immunity | Ability assessed in the presence of power-frequency magnetic disturbances. |
| Power over Ethernet (PoE) | Supplying electrical power and network data to compatible equipment through Ethernet cabling. |
| Process variable | A measured process quantity communicated by an instrument. |
| PROFIBUS Class 1 master | Controller role exchanging I/O data with its assigned PROFIBUS slaves. |
| PROFIBUS Class 2 master | PROFIBUS master role associated with diagnostics, configuration, and startup tools. |
| PROFIBUS DP | A fieldbus protocol for fast cyclic data exchange between a controller and distributed peripheral devices. |
| PROFIBUS DP-V0 | Original PROFIBUS DP version providing cyclic process-data exchange. |
| PROFIBUS DP-V1 | PROFIBUS DP extension adding acyclic master/slave data exchange. |
| PROFIBUS DP-V1 Abort service | Service terminating a Class 2 acyclic connection. |
| PROFIBUS DP-V1 Data Transport service | Class 2 service combining application-specific write and read exchange. |
| PROFIBUS DP-V1 Initiate service | Service establishing a Class 2 acyclic connection. |
| PROFIBUS DP-V1 Read service | Acyclic service retrieving an addressed device data block. |
| PROFIBUS DP-V1 slot-index addressing | Scheme identifying a module by slot and its data block by index. |
| PROFIBUS DP-V1 Write service | Acyclic service writing an addressed device data block. |
| PROFIBUS DP-V2 | PROFIBUS DP extension supporting direct slave communication with an isochronous bus cycle. |
| PROFIBUS MSAC_C1 | DP-V1 acyclic communication relationship associated with a Class 1 master. |
| PROFIBUS MSAC_C2 | DP-V1 acyclic communication relationship established by a Class 2 master. |
| PROFIBUS service access point (SAP) | Protocol access identifier selecting a communication service endpoint. |
| PROFINET | An industrial Ethernet communication system for exchanging data between automation controllers and devices. |
| PROFINET CBA | The PROFINET model organizing distributed automation as interconnected components. |
| PROFINET IO | The PROFINET model used for communication with distributed I/O and drives. |
| PROFINET IO device | A field device that exchanges its input and output data with a PROFINET controller. |
| PROFINET IRT | PROFINET communication with tightly synchronized timing for demanding motion applications. |
| PROFINET NRT | PROFINET communication using standard network protocols for tasks without strict real-time timing requirements. |
| PROFINET RT | PROFINET real-time communication for cyclic industrial I/O data exchange. |
| Protocol-based VLAN | VLAN classification based on traffic protocol. |
| Protocol gateway | A device that translates or maps information between different communication protocols. |
| Public-key infrastructure (PKI) | A framework of certificates and keys used to establish and manage digital trust. |
| Publish topic | The named MQTT channel under which a client sends messages. |
| Pulse-per-second output (PPS) | Timing output producing one pulse each second. |
| Pulse width modulation (PWM) | Controlling a digital output waveform's pulse width to regulate the effect on a connected load. |
| PWM output frequency | The number of complete PWM waveform cycles produced each second. |
| QoS (Quality of Service) | An MQTT setting specifying the message delivery assurance level. |
| QoS traffic policer | Mechanism metering traffic against configured limits and applying enforcement. |
| Radiated RF immunity | Ability assessed by exposing equipment to radiated radio-frequency disturbances. |
| Radio group ID | Radio-network grouping identifier used to distinguish compatible modem networks. |
| Raw data | Unscaled numerical values returned directly from an acquisition channel. |
| Reactive energy | Time accumulation of reactive power, commonly reported in kvarh. |
| Real-time clock (RTC) | A hardware clock that maintains calendar date and time for device operations. |
| Receive data (RxD) | RS-232 signal carrying data received by an endpoint. |
| Recipe | A predefined set of process settings applied together to configure an operation. |
| Reconnection interval | The delay before a client retries connecting after a failed connection. |
| Redundant power inputs | Separate power connections that help maintain operation if one supply fails. |
| Relay common terminal (COM) | The shared terminal forming one side of a relay's switched contact path. |
| Relay contact rating | The specified electrical load a relay contact can switch under stated conditions. |
| Relay electrical endurance | Specified contact switching life under stated electrical loading conditions. |
| Relay mechanical endurance | Specified number of mechanical operations for a relay. |
| Relay operate time | Time required for a relay to operate after energization. |
| Relay release time | Time required for a relay to release after de-energization. |
| Request to Send (RTS) | An RS-232 control signal used in hardware flow-control handshaking. |
| Resistive load | A load whose electrical behavior is predominantly resistive rather than inductive. |
| Resolution | The smallest measurement increment distinguishable by an input's digital representation. |
| RESTful API | A web interface that lets applications access device resources through HTTP requests. |
| Reverse-polarity protection | Circuit protection against an incorrectly connected DC power supply. |
| RF transmission bit rate | Configured speed for conveying data over the radio link. |
| Ring indicator (RI) | RS-232 signal indicating an incoming call condition. |
| RS-232 | A serial electrical interface with separate transmit, receive, and ground connections. |
| RS-485 | A differential serial electrical interface commonly used for shared industrial communication buses. |
| RSSI (Received Signal Strength Indicator) | A reported measure of the strength of a received radio signal. |
| RTD (Resistance Temperature Detector) | A temperature sensor whose electrical resistance changes with temperature. |
| Safe value | A configured output value applied when the communication watchdog times out. |
| Sampling rate | The number of measurements acquired per second. |
| Satellite-based augmentation system (SBAS) | Satellite-based correction service used to improve supported positioning results. |
| SCADA (Supervisory Control and Data Acquisition) | Software for supervising processes, collecting data, displaying trends, and managing alarms. |
| Scaling | Converting a numerical reading into the corresponding physical measurement using a defined relationship. |
| Scaling offset | A constant added during signal conversion to shift the converted value. |
| Scheduled PoE power reset | Timed interruption and restoration of PoE port power. |
| SDO (Service Data Object) | A CANopen communication object used to read or write object-dictionary parameters. |
| Security policy | A defined set of cryptographic algorithms used to protect OPC UA communication. |
| Selectable gain | A choice of amplification levels used to match a measurement signal to the required range. |
| Self-signed certificate | Certificate signed using its own associated private key. |
| Sensor excitation current | Current supplied to energize the electronics of a connected sensor. |
| Sensor short circuit | An unintended low-resistance connection in a sensor circuit. |
| Sequential Function Chart (SFC) | A PLC programming method that organizes a process into steps and transitions. |
| Serial data bits | The number of information bits carried in each serial character. |
| Serial stop bit | A signaling interval marking the end of an asynchronous serial character. |
| Setpoint | The target value that a controller attempts to maintain. |
| Settling time | The delay allowed for an analog input signal path to stabilize before measurement. |
| Short-circuit protection | A protective function that limits damage when an output encounters an unintended low-resistance connection. |
| Signal-to-noise ratio (SNR) | A measure comparing the desired signal level with the background noise level. |
| Signal amplification | Increasing a signal's amplitude so it can be measured or used by another circuit. |
| Signal conditioning | Preparing a sensor signal for measurement through amplification, filtering, range conversion, or isolation. |
| Signal range matching | Converting a signal's range to suit the input requirements of connected equipment. |
| SIM PIN | Code required to unlock a protected SIM for use. |
| SIM PUK | Unblocking code required when a SIM enters its PUK-required state. |
| Single-ended input | An analog input measured relative to a shared reference connection. |
| Single-mode fiber | Optical fiber used with compatible transceivers for longer-distance network links. |
| Sinking input | A digital input that provides a current path toward the circuit's negative reference. |
| SNMP (Simple Network Management Protocol) | A protocol used to monitor and manage network-connected devices. |
| SNMP agent | The component in a managed device that supplies management information and handles management requests. |
| SNMP engine ID | Identifier used in configuring an SNMPv3 engine/user relationship. |
| SNMP MIB view | Configured inclusion or exclusion of managed-object branches for access. |
| SNMP trap | An unsolicited notification sent by a managed device to report an event. |
| Soft PLC | Software that performs programmable logic control on a supported computing platform. |
| Software calibration | Adjusting measurement or output accuracy through software-controlled correction settings. |
| Software trigger | Acquisition trigger initiated by a software command rather than an external signal. |
| Sourcing input | A digital input that supplies current through a connected switching device toward the negative reference. |
| Sourcing output (PNP) | A digital output that supplies current from the positive supply to a connected load. |
| Span adjustment | Calibration adjustment that aligns the difference between a signal's lower and upper reference points. |
| Spanning Tree Protocol (STP) | Redundancy protocol used to prevent network loops while maintaining backup paths. |
| Split-core current transformer | Current transformer with an opening core allowing installation around a conductor. |
| SPST Form A relay | A single-pole, single-throw relay with a normally open contact. |
| Stateless Address Autoconfiguration (SLAAC) | IPv6 mechanism automatically deriving address configuration using network information. |
| Static IP address | An IP address assigned through fixed configuration rather than automatic allocation. |
| Static MAC forwarding entry | Manually configured association used in Ethernet frame forwarding. |
| Stepper motor | A motor driven through discrete commanded steps to control movement. |
| Store-and-forward | Switch processing that receives a complete frame before forwarding it. |
| Strain gauge | A sensing element whose electrical resistance changes with mechanical deformation. |
| Strict priority queuing | Scheduling that serves the highest-priority nonempty queue first. |
| Structured Text (ST) | A text-based PLC language used to express calculations, decisions, and control sequences. |
| Subnet mask | An IPv4 value separating the network and host portions of an address. |
| Subscriber identity module (SIM) | Card providing subscriber information for cellular network access. |
| Surge immunity | Ability assessed against specified surge disturbances applied during immunity testing. |
| Surge protector | A device that limits transient overvoltage reaching connected equipment. |
| Synchronous PWM output | Starting multiple PWM output channels together under a shared trigger. |
| Synchronous Serial Interface (SSI) | Clocked serial interface used to read absolute encoder position. |
| TACACS+ shared key | Secret shared between a network device and its TACACS+ authentication server. |
| TCP (Transmission Control Protocol) | A connection-oriented transport protocol providing reliable, ordered delivery of data. |
| TCP idle timeout | Configured inactivity interval after which an idle TCP connection is closed. |
| Temperature drift | A change in measurement or circuit characteristics caused by changing temperature. |
| Termination resistor | A resistor across a communication pair that reduces cable-end signal reflections. |
| Thermocouple | A temperature sensor that develops a temperature-dependent voltage at the junction of dissimilar conductors. |
| Thermocouple linearization | Converting a thermocouple's nonlinear voltage response into a temperature reading. |
| Three-way isolation | Electrical separation among a module's input, output, and power circuits. |
| Three-wire RTD | An RTD connection using an additional lead to compensate for lead resistance. |
| Timer pause | Temporarily stopping a timer while retaining the remaining interval. |
| Timer period | The configured duration a timer counts before reaching its timeout condition. |
| Timer reset | Stopping a timer and returning its accumulated timing state to the initial condition. |
| Timer resume | Continuing a paused timer from its retained timing state. |
| Timer timeout | The condition indicating that a timer's configured interval has elapsed. |
| TLS (Transport Layer Security) | A protocol that protects network communication through authentication, encryption, and integrity checks. |
| TLS server certificate | Certificate presenting a server's identity to connecting clients. |
| Token passing | A communication method that grants devices transmission permission in sequence. |
| Total volatile organic compounds (TVOC) | Aggregate measurement of volatile organic compounds in monitored air. |
| Transmit data (TxD) | RS-232 signal carrying data sent by an endpoint. |
| Transparent radio transmission | Radio transfer presenting user data without application-level protocol interpretation. |
| TTL I/O | Digital input/output using transistor-transistor-logic-compatible electrical levels. |
| Twisted-pair cable | Two insulated conductors twisted together, used for differential communication wiring. |
| Two's-complement measurement format | Signed binary data representation used for positive and negative measurement codes. |
| Two-wire RTD | An RTD connection using two leads, with lead resistance affecting the measurement. |
| Type C thermocouple input | Temperature-input setting using the Type C thermocouple conversion curve. |
| Type L thermocouple input | Temperature-input setting using a specified Type L thermocouple curve. |
| Type M thermocouple input | Temperature-input setting using the documented Type M conversion curve. |
| UCMM (Unconnected Message Manager) | A mechanism for accessing CIP objects without first establishing a CIP connection. |
| UDP (User Datagram Protocol) | A transport protocol that sends datagrams without establishing a reliable delivery connection. |
| Unipolar signal range | A signal range with values on only one side of zero. |
| Universal PCI interface | PCI interface supporting both 3.3 V and 5 V PCI buses. |
| Upper cutoff frequency | The upper frequency boundary of a signal conditioner's specified response. |
| USB bus-powered I/O | I/O equipment receiving operating power through its USB connection. |
| VLAN identifier (VID) | Numerical value identifying a tagged virtual LAN. |
| VLAN tag protocol identifier (TPID) | Ethernet field identifying the VLAN tagging format. |
| VLAN translation | Mapping that changes a frame's VLAN association between network boundaries. |
| Voltage attenuator | A device that reduces an input voltage to a lower measurement level. |
| Weighted fair queuing | Scheduling that allocates service across queues using configured relative weights. |
| Wet contact | An input connection whose state is indicated by an externally applied voltage. |
| Wi-Fi ad-hoc mode | Wireless mode allowing participating nodes to communicate directly without an access point. |
| Wi-Fi infrastructure mode | Wireless arrangement where clients connect through an access point. |
| Wi-Fi station mode | Mode where a Wi-Fi device joins an access point as a client. |
| Zero adjustment | Calibration adjustment that aligns a signal's lower reference point. |
| ZigBee | A low-power wireless networking technology based on IEEE 802.15.4 for connecting distributed devices. |
| ZigBee coordinator | Network role initializing and managing the ZigBee network. |
| ZigBee PAN ID | Group identifier used to distinguish a ZigBee network. |
| ZigBee router | ZigBee node role forwarding traffic between parent or child nodes. |
No matching terms found.
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