OPC Specification (sidebar)

Dec. 1, 2004
Data Access (DA): Original and most popular specification. Often used to move discrete quantities of real-time data from PLCs, DCSs, and other control devices to data clients.

Current Version/Release Date- / 2003-03-05

Historical Data Access (HDA): While OPC DA provides access to real-time data, OPC HDA provides access to previously saved time series data. Current Version/Release Date- / 2003-12-10

XML Data Access (XML-DA): Provides similar functionality to the DA specification but uses Web Services instead of DCOM to enable widely distributed, loosely coupled systems to exchange data across firewalls. Current Version/Release Date- / 2003-07-12

Complex Data: Companion to OPC DA that permits more complicated data types such as binary structures and XML documents. Current Version/Release Date- / 2003-12-10

Data eXchange (DX): Enables server-to-server communication Current Version/Release Date- / 2003-03-11

Alarms & Events (A&E): Provides alarm and event notifications on demand, including process alarms, operator actions, informational messages, and tracking/auditing messages. Current Version/Release Date- / 2002-10-02

Batch: Enables batch control and information systems to exchange batch and recipe data per ISA-88. Current Version/Release Date- / 2001-07-19

Security: Addresses security issues as they relate to the OPC interfaces. Current Version/Release Date- / 2001-01-26

Commands: Enables clients to issue commands to and receive status from servers for state driven objects. Current Version/Release Date-In Progress

Unified Architecture (UA): Next generation, Web Service and XML based, OPC interfaces. Current Version/Release Date-In Progress

See the story that goes with this sidebar: Many Devices, One Solution