About the Historian User API

The Historian User API provides high-speed read/write access to Historian data and read access to Historian tags. There is no access to archives, alarms, events, or messages.

Use this API to develop applications that read and write data to the Historian server when the Historian SDK and Historian OLE DB do not meet your project requirements for performance or programming language.

Note: At this time, the Historian User API supports single-byte strings only.
The Historian Client Access API is a .NET Core assembly that interacts with Historian from any .NET Core applications. Since the API uses .NET Core, you can use it on any operating system. The required DLLs are available in the DotNetCoreCAAPI folder in the ISO. This folder also contains a sample program, which you can use a starting point to build an application.
Note: You can still use the old Client Access API, which is a .NET assembly. You can use this API only on Windows. It is installed when you install Historian Client Tools. By default, the Install Wizard places both the API and Client Access .dlls in GAC (Global Assembly Cache). It is recommended that you add Historian Client Access API references from the INSTALLPATH directory since global assembly cache is part of the run-time environment.
The applications that call into the User API are limited by the security access granted at the server level.