Overview

The OPC Alarm and Events specification defines a means for transmitting alarm and event information between OPC servers and clients. Alarms and events are process alerts that require attention and are defined as follows.

An alarm is an abnormal condition, for example, a tank level alarm (which may also have these sub-conditions, LO, LOLO, HI, and HIHI).

An event is a detectable occurrence that usually concerns configuration changes, operator action, system messages or errors.

This document uses the same terms and definitions found in the OPC Alarms and Events Custom Interface Document v. 1.10; and the terms alarm and event are used interchangeably.

The PI Interface for OPC Alarms and Events (PI OPCAE) receives both alarm and event data, including all three event types (Simple, Tracking-related, and Condition-related.

The PI OPCAE interface is extremely flexible in how it can store the alarms and events data. Alarm and event attributes can be chosen separately as part of the data that will be stored in PI. All chosen data can be stored in a single tag with the fields delimited by the pipe (|) symbol or can be stored into separate PI tags.

The interface transfers data to the PI Data Archive from these systems:

• An OPC Alarms and Events Server

• An OPC DA Server that supports the OPC Alarms and Events interface.