Word | Definition |
| API | Application Programming Interface (API) is a set of software functions used by an application program as a means for providing access to a specific application or operating system's capabilities. |
| Browse | An OPC interface that enables an OPC client application to view all of the available tag items of an OPC server. |
| Central Processing Unit | Central Processing Unit (CPU) is the main processing chip of a computer. the part of the computer or computer system which performs core processing functions. |
| Client | A software program that is used to contact and obtain data from a Server software program either on the same computer or on another computer. A client makes a request and the server fulfills the request. An example of a client would be an e-mail program connecting to a mail server or an Internet browser client connecting to a web server. In the case of OPC, an HMI would be a client application that connects to an OPC sever. Also related is Server. |
| COM | Component Object Model (COM) is a Microsoft concept used to communicate between components on the same computer. Components from different machines can be combined using DCOM (See DCOM). |
| Component Object Model | Component Object Model (COM) is a Microsoft concept used to communicate between components on the same computer. Components from different machines can be combined using DCOM (See DCOM). |
| COTS | Commercial off-the-shelf (COTS) is commercially available products that are purchased and integrated with little configuration. Typically COTS reduces integration cost and time. |
| CPU | Central Processing Unit (CPU) is the main processing chip of a computer. the part of the computer or computer system which performs core processing functions. |
| CRC | Cyclical Redundancy Check (CRC) is a procedure used to check for errors in data transmission. |
| Cyclical Redundancy Check | Cyclical Redundancy Check (CRC) is a procedure used to check for errors in data transmission. |
| DAQ | Also known as Data Acquisition, DAQ is the collection and measurement of signals from sensors, transducers, and probes for processing. |
| DAS | Also known as Data Acquisition System, DAQ is a system of one or more sensors, devices and communication links used to scan or collect and forward data to a central location for further processing, display, or archiving. |
| Data Acquisition System | Also known as DAQ, Data Acquisition System is a system of one or more sensors, devices and communication links used to scan or collect and forward data to a central location for further processing, display, or archiving. |
| Database | A database is an organized collection of information in digital or electronic format. |
| DCOM | Distributed Component Object Model (DCOM) is a set of Microsoft concepts and program interfaces in which client program objects can request services from server program objects on other computers in a network. DCOM is based on the Component Object Model (COM), which provides a set of interfaces allowing clients and servers to communicate within the same computer. |
| DCS | Distributed Control System (DCS) is a big Programmable Logic Controller (PLC) that is typically networked to other controllers, PLCs or field devices. It typically has a workstation to interface with the controller and can be very expensive due to built-in security and fail-over features. |
| DDE | Dynamic Data Exchange (DDE) is a form of InterProcess Communication (IPC) in the Microsoft Windows operating environment. When two or more applications that support DDE are running simultaneously, they can exchange information, data and commands. DDE has been enhanced with Object Linking and Embedding (OLE) technology. |
| Dead-Band | Dead-Band is the range through which the input may be varied without initiating a response. |
| Distributed Component Object Model | Distributed Component Object Model (DCOM) is a set of Microsoft concepts and program interfaces in which client program objects can request services from server program objects on other computers in a network. DCOM is based on the Component Object Model (COM), which provides a set of interfaces allowing clients and servers to communicate within the same computer. |
| Distributed Control System | Distributed Control System (DCS) is a big Programmable Logic Controller (PLC) that is typically networked to other controllers, PLCs or field devices. It typically has a workstation to interface with the controller and can be very expensive due to built-in security and fail-over features. |
| Domain | A collection of computers on a network that share a common database and security policy. A domain is administered as a unit with common rules and procedures, and each domain has a unique name. |
| Dynamic Data Exchange | Dynamic Data Exchange (DDE) is a form of InterProcess Communication (IPC) in the Microsoft Windows operating environment. When two or more applications that support DDE are running simultaneously, they can exchange information, data and commands. DDE has been enhanced with Object Linking and Embedding (OLE) technology. |
| Extensible Markup Language | Extensible Markup Language (XML) is a flexible way to create standard information formats and share both the format and the data on the World Wide Web and with disparate operating systems. |
| GPI | General Purpose Interface |
| Graphical User Interface | Graphical User Interface (GUI) enables a user to interact with a software application through graphics instead of text. |
| GUI | Graphical User Interface (GUI) enables a user to interact with a software application through graphics instead of text. |
| Historian | A historian is a type of database designed to store process data. Due to the enormous amount of process data some plants produce, some historians compress data using algorithms. Others historians are designed to act as a "rolling buffer" and are able to store high frequency data. |
| HMI | Human Machine Interface (HMI) is a software application (typically a Graphical User Interface or GUI)that present information to the operator about the state of a process, and to accept and implement the operators control instructions. It may also interpret the plant information and guide the interaction of the operator with the system. Also known as Man Machine Interface (MMI). |
| Human Machine Interface | Human Machine Interface (HMI) is a software application (typically a Graphical User Interface or GUI)that present information to the operator about the state of a process, and to accept and implement the operators control instructions. It may also interpret the plant information and guide the interaction of the operator with the system. Also known as Man Machine Interface (MMI). |
| Interoperability Testing | Interoperability Testing is a process where OPC vendors attend an event hosted by the OPC Foundation and test their products with the products supplied by other OPC vendors. These events are called Interoperability (IOP) Workshops.
The interoperability test process requires that OPC vendors run a series of standard tests for each combination of an OPC Client and an OPC Server product. The results of these tests are collected and displayed in the product catalogue. In Addition OPC Client Products can be tested against the OPC Analyzer Tool in a test monitored by the OPC Foundation. Clients that pass testing with this tool will result in an OPC Client Product listed as "Self Tested". |
| Inter-Process Communication (IPC) | Inter-Process Communication (IPC) transfers information between processes or between the kernel and a process. |
| Internet Protocol | Internet Protocol (IP) is the basic network transmission protocol of the Internet. |
| IOP Workshops | See Interoperability Workshops. |
| IP | Internet Protocol (IP) is the basic network transmission protocol of the Internet. |
| IPC | Inter-Process Communication (IPC) transfers information between processes or between the kernel and a process. |
| LAN | Local Area Network (LAN) is a computer network typically limited to a small geographic area, usually the same building/plant or floor of a building/plant. |
| Local Area Network | Local Area Network (LAN) is a computer network typically limited to a small geographic area, usually the same building/plant or floor of a building/plant. |
| Man Machine Interface | Man Machine Interface (MMI) is a software application (typically a Graphical User Interface or GUI)that present information to the operator about the state of a process, and to accept and implement the operators control instructions. It may also interpret the plant information and guide the interaction of the operator with the system. Also known as Human Machine Interface (HMI). |
| MMI | Man Machine Interface (MMI) is a software application (typically a Graphical User Interface or GUI)that present information to the operator about the state of a process, and to accept and implement the operators control instructions. It may also interpret the plant information and guide the interaction of the operator with the system. Also known as Human Machine Interface (HMI). |
| ODBC | Open DataBase Connectivity (ODBC) is a Microsoft standard for accessing different database systems from Windows such as SQL, Access or Oracle. |
| OPC | OPC is a set of standard interfaces based upon Microsoft's OLE/COM technology. The application of the OPC standard interface makes possible interoperability between automation/control applications, field systems/devices etc. |
| OPC A&E | OPC Alarms and Events (OPC A&E) is used to exchange process alarms and events. OPC A&E can be used by operations to notify them of alarms and obtain a sequence of events. |
| OPC Alarms & Events | OPC Alarms and Events (OPC A&E) is used to exchange process alarms and events. OPC A&E can be used by operations to notify them of alarms and obtain a sequence of events. |
| OPC Batch | OPC Batch is a specification published by the OPC Foundation. This specification carries the OPC philosophy to the specialized needs of batch processes. It provides interfaces for the exchange of equipment capabilities (corresponding to the S88.01 Physical Model) and current operating conditions. |
| OPC Commands | A specification published and maintained by the OPC Foundation. OPC Commands defines a new set of interfaces that allow OPC clients and servers to identify, send and monitor control commands which execute on a device. |
| OPC Complex Data | OPC Complex Data is a standard published by the OPC Foundation. It is a companion specification to OPC Data Access and OPC XML-DA that allows servers to expose and describe more complicated data types such as binary structures and XML documents. |
| OPC Compliance |  The OPC Foundation offers certification to ensure that OPC servers meet the defined specification. The OPC Foundation has produced automated tools used for vendors to test their OPC products. Those products that past the test can be classified as OPC Certified and display the OPC Compliance logo. |
| OPC Compliant | The OPC Foundation offers certification to ensure that OPC servers meet the defined specification. The OPC Foundation has produced automated tools used for vendors to test their OPC products. Those products that past the test can be classified as OPC Certified and display the OPC Compliance logo. |
| OPC DA | OPC Data Access (OPC DA) provides access to real time process data. Using OPC DA, one can ask the OPC server for the most recent value of flows, pressures, levels, temperatures, densities, and more. For historical data see OPC Historical Data Access (OPC HDA). |
| OPC Data Access | OPC Data Access (OPC DA) provides access to real time process data. Using OPC DA, one can ask the OPC server for the most recent value of flows, pressures, levels, temperatures, densities, and more. For historical data see OPC Historical Data Access (OPC HDA). |
| OPC Data eXchange (OPC DX) | OPC Data eXchange (OPC DX) is a specification defines how OPC servers exhange data with other OPC servers. |
| OPC Driver | An OPC Driver is a software application that acts as an API (Application Programming Interface) or protocol converter. An OPC Driver will connect to a device such as a PLC, DCS, RTU, etc or a data source such as a database, HMI, etc and translate the data into a standard-based OPC format. OPC compliant applications such as an HMI, historian, spreadsheet, trending application, etc can connect to the OPC Driver and use it to read and write device data. An OPC Driver is analogous to the roll a printer driver plays to enable a computer to communicate with an ink jet printer. An OPC Driver is based on a Server/Client architecture. |
| OPC DX | OPC Data eXchange (OPC DX) is a specification defines how OPC servers exhange data with other OPC servers. |
| OPC Foundation | The OPC Foundation is made up of over 350 companies, organizations and individuals. They are responsible for developing and maintaining the OPC Specifications and ensuring product interoperability and compliance. Visit the OPC Foundation's website at www.opcfoundation.org. |
| OPC HDA | OPC Historical Data Access (OPC HDA) is used to retrieve and analyze historical process data, which is typically stored in a Process Data Archiver, a database, or an RTU. For real-time data, see OPC Data Access (OPC DA). |
| OPC Historical Data Access | OPC Historical Data Access (OPC HDA) is used to retrieve and analyze historical process data, which is typically stored in a Process Data Archiver, a database, or an RTU. For real-time data, see OPC Data Access (OPC DA). |
| OPC Interoperability Workshops | The OPC Foundation arranges workshops hosted by member companies, where participants can test their latest OPC devices. This helps ensure that multi-vendor products interoperate with one another. Successfully tested client/server pairs are published on the OPC Foundation’s website. |
| OPC Security | OPC Security is a standard published by the OPC Foundation. OPC Security specifies how to control client access to servers in order to protect sensitive information and to guard against unauthorized modification of process parameters. |
| OPC Server | An OPC Sever is a software application that acts as an API (Application Programming Interface) or protocol converter. An OPC Server will connect to a device such as a PLC, DCS, RTU, etc or a data source such as a database, HMI, etc and translate the data into a standard-based OPC format. OPC compliant applications such as an HMI, historian, spreadsheet, trending application, etc can connect to the OPC Server and use it to read and write device data. An OPC Server is analogous to the roll a printer driver plays to enable a computer to communicate with an ink jet printer. An OPC Server is based on a Server/Client architecture. |
| OPC Tunnelling Technology | OPC technology that transfers process data between networked computers using TCP/IP instead of DCOM. |
| OPC UA | OPC Unified Architecture (OPC UA) will replace, modernize and enhance all the functionality of the existing OPC defined interfaces. OPC UA is described in a layered set of specifications broken into Parts. It is purposely described in abstract terms and in later parts married to existing technology on which software can be built. This layering is on purpose and helps isolate changes in OPC UA from changes in the technology used to implement it. |
| OPC Unified Architecture | OPC Unified Architecture (OPC UA) will replace, modernize and enhance all the functionality of the existing OPC defined interfaces. OPC UA is described in a layered set of specifications broken into Parts. It is purposely described in abstract terms and in later parts married to existing technology on which software can be built. This layering is on purpose and helps isolate changes in OPC UA from changes in the technology used to implement it. |
| OPC XML | OPC Extensible Markup Language (OPC XML) encapsulates process control data making it available across all operating systems. |
| Open DataBase Connectivity | Open DataBase Connectivity (ODBC) is a Microsoft standard for accessing different database systems from Windows such as SQL, Access or Oracle. |
| Operating System | Operating System (OS) is a software program, which manages the basic operations of a computer system. These operations include memory appointment, the order and method of handling tasks, flow of information into and out the main processor and to peripherals, etc. |
| OS | Operating System (OS) is a software program, which manages the basic operations of a computer system. These operations include memory appointment, the order and method of handling tasks, flow of information into and out the main processor and to peripherals, etc. |
| PDU | Protocol Design Utility |
| PLC | Programmable Logic Controller (PLC) is an industrial device that provides an interface for input sensors and output actuators. PLCs can be programmed using relay ladder logic to control the outputs based on input conditions and / or algorithms contained in the memory of the PLC. |
| Polling | Polling is the process in which a number of peripheral devices, remote stations, or nodes within a plant-based or SCADA network are accessed by a client application via a server to read and write data. |
| Process Historian | A process historian is a type of database designed to store process data. Due to the enormous amount of process data some plants produce, some process historians compress data using algorithms. Other process historians are designed to act as a "rolling buffer" and are able to store high frequency data. |
| Programmable Logic Controller | Programmable Logic Controller (PLC) is an industrial device that provides an interface for input sensors and output actuators. PLCs can be programmed using relay ladder logic to control the outputs based on input conditions and / or algorithms contained in the memory of the PLC. |
| PTU | Protocol Test Utility |
| Radio Frequency Identification | Also known as RFID, it is a technology that has existed for decades. At a simple level, it is a technology that involves tags that emit radio signals and devices called readers that pick up the signal. |
| Relational Database | A relational database is a collection of data items organized in a set of pre-defined tables from which data can be accessed without reorganizing the tables. |
| Remote Terminal Unit | Remote Terminal Unit (RTU) is an industrial data collection device typically located at a remote location and communicates data to a host system by using telemetry (such as radio, dial-up telephone, or leased lines). |
| RFID | RFID stands for Radio Frequency Identification. It is a technology that has existed for decades. At a simple level, it is a technology that involves tags that emit radio signals and devices called readers that pick up the signal. |
| RTU | Remote Terminal Unit (RTU) is an industrial data collection device typically located at a remote location and communicates data to a host system by using telemetry (such as radio, dial-up telephone, or leased lines). |
| SBC | Single Board Computer |
| SCADA | Supervisory Control and Data Acquisition (SCADA) is a common process control application that collects data from sensors on the shop floor or in remote locations and sends them to a central computer for management and control. |
| Server | A software application designed to bridge the communication between a device, controller or data source with a client application. Servers can only respond to requests made by a client. An example would be an HMI, an client, asking the OPC server for the latest value of a particular process value. Also related is Client. |
| Set-Point | The set-point is defined as the value where you would like a process variable to be. For example, the temperature of a boiler may have a set-point of 100 degrees or a flow valve has a set-point of 50 gallons per minute. |
| Supervisory Control and Data Acquisition | Supervisory Control and Data Acquisition (SCADA) is a common process control application that collects data from sensors on the shop floor or in remote locations and sends them to a central computer for management and control. |
| TCP/IP | Transmission Control Protocol/Internet Protocol (TCP/IP is the basic communication language or protocol of the Internet. |
| Transmission Control Protocol/Internet Protocol | Transmission Control Protocol/Internet Protocol (TCP/IP is the basic communication language or protocol of the Internet. |
| UDP | User Datagram Protocol (UDP) transports data as a connectionless protocol, using packet switching. |
| User Datagram Protocol | User Datagram Protocol (UDP) transports data as a connectionless protocol, using packet switching. |
| VB | Visual Basic (VB) is a popular Microsoft programming language used by software vendors and developers to build graphical client application interfaces. |
| Virtual Memory System | Virtual Memory System (VMS) is the operating system on a VAX node (also related is Open Virtual Memory System - OpenVMS). |
| Visual Basic | Visual Basic (VB) is a popular Microsoft programming language used by software vendors and developers to build graphical client application interfaces. |
| WAN | Wide Area Network (WAN) is a computer network covering a large geographical area, usually consisting of two or more LANs. |
| Wide Area Network | Wide Area Network (WAN) is a computer network covering a large geographical area, usually consisting of two or more LANs. |
| Workgroup | A group of computers that are connected on a network and share resources, such as printers and files. When you set up a network, Windows automatically creates a workgroup and gives it a name. |
| XML | Extensible Markup Language (XML) is a flexible way to create standard information formats and share both the format and the data on the World Wide Web and with disparate operating systems. |
