What is OPC Historical Data Access (HDA)?

What is OPC Historical Data Access (OPC HDA)? What is it used for?

Defined by the OPC Foundation to complement real-time OPC Data Access (DA), the classic OPC HDA standard provides an open, plug-and-play mechanism to retrieve and analyze stored process data from OPC HDA-enabled server applications like databases and historians. Mixtures of raw, interpolated, and aggregated data are typically supported for exchange between OPC HDA clients and OPC HDA servers. Like OPC DA, OPC HDA is built on Microsoft’s Component Object Model (COM), which provides built-in user authentication, authorization, and message encryption. Clients and servers can be located on the same OS or on separate operating systems that share an Ethernet network.

Benefits of OPC HDA

OPC HDA standardizes the collection of archived process data, seeking to turn what had been bespoke, custom, difficult integrations around large, historical data sets into quick, plug-and-play connections. The specification includes support for server and data item browsing, local and remote collection interfaces, and mixtures of raw, interpolated, and aggregated data sets.

Standardized access to Historical data

OPC HDA standardizes integration between clients and historical data servers, yielding faster time to value with less cost spent on custom engineering.

Server and data discovery

OPC HDA supports server and data discovery features, reducing integration complexity, and offering plug-and-play connection management.

Built on COM/DCOM

OPC HDA is built on Microsoft Windows native COM and DCOM IPC technology, allowing tightly coupled and secure local and remote connections within and across Windows operating systems.

Interoperability and OPC HDA

OPC HDA standardizes integration between clients and historical data servers, yielding faster time to value with less cost spent on custom engineering. Applications that are built to OPC HDA standards can enjoy plug-and-play interoperability with no customization or proprietary modifications required.

Applications of OPC HDA

Process Improvement

For customers seeking process-improvement tools, OPC HDA clients and servers can be used to collect, store, and analyze process data.

Distributed and Centralized Historical Data

OPC HDA applications can be used by enterprises for many solutions, from centralized data historians to local operations monitoring and troubleshooting.

Buffer and Store Critical Process Data

OPC HDA servers can act quickly to capture and commit data to file systems, enabling data to be held safely at rest until collection occurs.

Local Historian Plug-In for Kepware

The Local Historian moves data collection, storage, and access closer to the data source to prevent data loss and improve operational efficiency via open access and a single product solution. By plugging into Kepware, the Local Historian can connect to any device and begin historizing data in real time without operational downtime. The advanced plug-in architecture simplifies configuration, provides flexibility, and makes the information accessible across OPC HDA. .

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Plug-in features

The Local Historian is an optional feature of Kepware Server that collects, persists, manages, and serves historical process data to clients with minimal configuration.

Ability to collect a value, quality, and timestamp from any data source in the Kepware server (e.g., drivers, plug-ins, or system tags).

Collection from both static and dynamic server tags.

Persistence to a volume on the local machine, which can be a fixed drive or removable media.

Provides (serves) access to historical data via OPC HDA v1.20.

Support for collection deadband.

Configurable data collection scan rates, as frequently as 10 milliseconds.

Configurable data retention policy.

Support for data timestamps with one millisecond resolution.

Ability to import historical data that has been backed up and removed from active use.

Frequently asked questions

Does OPC UA support HDA?

The OPC Unified Architecture (UA) specification includes a modernized implementation of historical data handling called Historical Access (OPC UA-HA).

How does OPC HDA work?

The OPC HDA standard utilizes Microsoft’s Component Object Model (COM) inter-process communication (IPC) framework to create tightly coupled, Windows-based data storage, access, and analysis applications. Applications that implement the OPC HDA server-side portion of the OPC HDA standard obtain data from data sources, store the obtained data, and then serve the obtained data to requesting clients. Clients are expected to implement the client-side portion of the OPC HDA standard to make requests to OPC HDA servers.

What is the relationship between OPC HDA and other standard specifications like OPC DA, OPC AE, and OPC UA?

OPC HDA is a stand-alone protocol standard that defines how to request and serve historical data typically related to manufacturing processes. It is considered an “OPC Classic” standard because it was created around the same time as and using the same IPC framework (COM) as OPC DA and AE. OPC HDA, OPC DA, and OPC AE have been officially deprecated by the OPC Foundation, but commercial software brands like Kepware still build and support OPC HDA-based products.

OPC Historical Data Access (HDA)