Terminology of PI APS

Attribute

A parameter that describes a PI point. Each PI point has an associated list of attributes. Some attributes are descriptive. Other attributes are configuration parameters for the PI Server, the interface instance that transfers data between the PI point and data source, or both.

COM Connector

A COM object that allows the PI Server to access data from a foreign data historian and make it available to any PI client application in a seamless fashion. Some currently available PI COM Connectors include those for data historians from AspenTech and Honeywell, as well as one for any data source with an OLEDB provider. PI COM Connectors are only available on Windows platforms.

DCS

An acronym for Distributed Control System. DCS was used in earlier versions of this manual as a generic term for any data source that provides data to a PI Server, including measurement and control systems or other historian systems, even other PI Servers.

ICU

The PI Interface Configuration Utility. The ICU is the primary application that you use to configure and run PI interface programs. You must install the ICU on the same computer on which an interface runs. A single copy of the ICU manages all of the interfaces on a particular computer.

You can configure and run an interface by editing a startup command file. However, PI APS cannot access interface parameters from a startup command file. Therefore, configuring an interface instance with the ICU is a prerequisite to registering the interface instance with PI APS.

Interface

A software program that collects data from some type of data source and sends the data to a PI Server. Some interfaces also have the ability to read data from a PI Server and write back to the data source.

In this manual, interface is used as a generic term for either a classic PI interface or PI COM Connector.

Interface node

A computer on which

• The PI API and/or PI SDK are installed, and

• PI Server is not installed.

PI API

A library of functions that PI client applications call to communicate and exchange data with the PI Server. All PI interfaces use PI API.

PI Collective

Two or more replicated PI Servers that collect data concurrently. Collectives are part of the High Availability environment. When the primary PI Server in a collective becomes unavailable, a secondary collective member node seamlessly continues to collect and provide data access to your PI clients.

PIHOME

The directory that is the common location for 32-bit PI client applications.

A typical PIHOME on a 32-bit operating system is C:\Program Files\PIPC.

A typical PIHOME on a 64-bit operating system is C:\Program Files (x86)\PIPC.

PI 32-bit interfaces reside in a subdirectory of the Interfaces directory under PIHOME. Most PI APS files are in the APS subdirectory under PIHOME.

PIHOME64

The directory that is the common location for 64-bit PI client applications.

A typical PIHOME64 is C:\Program Files\PIPC.

PI 64-bit interfaces reside in a subdirectory of the Interfaces directory under PIHOME64.

pipc.log

The file to which OSIsoft applications write informational and error messages. While a PI interface runs, it writes to the pipc.log file. The ICU and PI APS Configuration Utility provide easy access to the pipc.log. The pipc.log file is in the dat subdirectory of PIHOME.

PI SDK

A library of functions that client applications call to communicate and exchange data with the PI Server. Some PI interfaces, in addition to using the PI API, require the use of the PI SDK. PI APS uses PI SDK to communicate with the PI Server.

PI Server node

A computer on which PI Server programs are installed. The PI Server runs on the PI Server node.

PI SMT

PI System Management Tools. PI SMT is the program that you use for configuring PI Servers. A single copy of PI SMT manages multiple PI Servers. PI SMT runs on either a PI Server node or a PI Interface node.

Point

The basic building block for controlling data flow to and from the PI Server. For a given time stamp, a PI point holds a single value.

A PI point does not necessarily correspond to a "point" on the data source. For example, a single "point" on the data source can consist of a set point, a process value, an alarm limit, and a discrete value. These four pieces of information require four separate PI points.

In this manual, "point" means a PI point and "tag" designates a point on the data source.

Service

A Windows program that runs without user interaction. A service has the ability to start up when the computer itself starts up. If started manually, the service continues to run after you log off from Windows.

Tag

The name of the PI point. There is a one-to-one correspondence between the name of a point and the point itself. Because of this relationship, PI System documentation uses the terms tag and point interchangeably.

In this manual, point means a PI point and tag designates a point on the data source.

UniInt (Universal Interface)

A framework for interfaces to the PI Server. UniInt provides common features and generic functions required by most interfaces. Most interfaces developed by OSIsoft are based on the UniInt framework, which results in a consistent set of features in the OSIsoft interfaces to PI. For example, the UniInt framework supports special points that can be used to monitor the performance and health of an interface. The UniInt framework also supports a failover mechanism for interface redundancy. The PI Universal Interface (UniInt) Framework user guide provides complete information about the features provided by UniInt.