Sources of data
- Last UpdatedDec 12, 2025
- 3 minute read
Historian can accept data from a number of sources. The most typical scenario is data acquisition from an I/O server.
Data acquisition from I/O servers
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An I/O server provides data from plant floor devices to AVEVA Historian using the SuiteLink or Dynamic Data Exchange (DDE) protocol. First, the I/O server collects data values from programmable logic controllers (PLCs), Remote Telemetry Units (RTUs), and similar devices on the factory floor. Then, the I/O server uses the SuiteLink or DDE protocol to time and quality stamp each data value it collect. Next, it passes the data values through the Data Acquisition subsystem, or IDAS. IDAS seamlessly handles data values,regardless of their time. Note: The SuiteLink protocol can be used to collect data from an I/O server on the same or different computer than the IDAS instance. The DDE protocol can be used only when the I/O server is on the same computer as the IDAS instance. For each data value acquired by IDAS, the timestamp, value, and quality are attached. |
Then the values are sent through the Historian Client Access Layer (HCAL) to a Historian Client Access Point (HCAP) on the Historian server, and then to storage. HCAL is a client-side software layer that provides programmatic access to storage, retrieval, and system configuration functionality in the AVEVA Historian.
Historian accepts and historizes each data value according to the storage rules for the tag to which the data value belongs.
For more details, see Configure data acquisition in the AVEVA Historian Administration Guide.
Other data acquisition options
As this diagram illustrates, AVEVA Historian can accept data from a range of sources.
In addition to I/O servers, Historian can acquire data from these sources:
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TransactSQL INSERT and UPDATE statements
You can insert or update history data in the AVEVA Historian extension tables using Transact-SQL INSERT and UPDATE statements.For more information, see Import, insert, or update history data in the AVEVA Historian Administration Guide.
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CSV and LGH files
Using the Historian Data Importer utility (aahImport), you can add history data from a file to AVEVA Historian. This utility reads data from InTouch history (LGH) files or comma-separated value (CSV) files, and then sends the data to the Historian server via HCAL.Imported data is integrated with data currently stored in history blocks, providing you with seamless access to all your data.
For more information, see Import, insert, or update history data in the AVEVA Historian Administration Guide.
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App Server, custom SDK client applications, tier-1 replication, and other sources
These sources are also able to use HCAL to send data to Historian. -
AVEVA Historian itself
Configuration data comes from the Historian itself.