Historian User API Overview

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.

Prerequisites

You must run the programs you create with the Historian User API on a machine with the following software installed and configured:

  • Historian 5.5 or greater
  • Historian 5.5 or greater Client Tools

The Historian User API has been tested with Visual Studio .NET 2003, 2005, and 2008.

The Historian User API has no additional hardware requirements.

Historian allows you to develop both 32-bit and 64-bit User API programs.

Note: To build a 32-bit User API program on a 64-bit operating system, you must rename ihuapi32.lib to ihuapi.lib and include it in your program.