For the purposes of this document, the terms and definitions given in the following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments and errata) applies.

OPC 10000-1, OPC 10000-3, and OPC 10000-4as well as the following apply.

link to arbitrary, live automation data, that is, data that represents currently valid information

Note 1to entry: Examples of such data are

  • device data (such as temperature sensors),
  • calculated data,
  • status information (open/closed, moving),
  • dynamically-changing system data (such as stock quotes),
  • diagnostic data.

DataItemsthat represent continuously-variable physical quantities (e.g., length, temperature), in contrast to the digital representation of data in discrete items

Note 1to entry: Typical examples are the values provided by temperature sensors or pressure sensors. OPC UA defines a specific VariableTypeto identify an AnalogItem. Propertiesdescribe the possible ranges of AnalogItems.

DataItems that represent data that may take on only a certain number of possible values (e.g., OPENING, OPEN, CLOSING, CLOSED)

Note 1to entry: Specific VariableTypesare used to identify DiscreteItemswith two states or with multiple states. Propertiesspecify the string values for these states.

DataItemsthat represent continuously-variable physical quantities and where each individual data point consists of multiple values represented by an array (e.g., the spectral response of a digital filter)

Note 1to entry: Typical examples are the data provided by analyser devices. Specific VariableTypesare used to identify ArrayItem variants.

units of measurement for AnalogItemsthat represent continuously-variable physical quantities (e.g., length, mass, time, temperature)

Note 1to entry: This standard defines Propertiesto inform about the unit used for the DataItemvalue and about the highest and lowest value likely to be obtained in normal operation.