PI API Overview

The PI Application Programming Interface (PI API) is intended to provide a common programmatic interface to PI information from the Point Database, the Archive, and PI Tables, as well as providing utilities for data collection interfaces and user application development. The PI API library has ANSI C functions so that code written with the PI API is portable across multiple hardware and software environments. 

There are two versions of PI API available for download.

PI API 2016 for Windows Integrated Security (2.0.1.35) brings significant security enhancements for PI Data Archive client applications, as well as reducing overall risk to the PI system in general. PI API 2016 for Windows Integrated Security does not support PI trusts or explicit logins. Windows authentication is the only supported authentication model for PI API-based client applications, such as PI interfaces. Windows Integrated Security is a more secure authentication model than PI trusts for authenticating users. PI Data Archive 3.4.380.36 or later is required for Windows authentication. 

PI API 1.6.8.x and older versions support connectivity to all versions of PI Data Archive and rely on trusts and explicit logins.

Support for buffering or caching data across network and maintenance events that interrupt communication are built into the PI API software so that data sent to a PI Server will arrive without the program requiring complicated recovery logic. Buffering in the PI API provides PI Server Collective (HA) support for data writing, but no other functionality in the PI API supports HA (reading data or point database information).