Apis Chronical

Apis Chronical is an event-server and historian designed to efficiently monitor, store, and retrieve large numbers of events and alarms.

Features:

  • Customizable EventType hierarchy based on the OPC UA event model
  • Multiple independent EventSource hierarchies
  • User interface for configuration, monitoring and querying
  • Online incremental backups
  • Standard OPC UA AC interface for event subscriptions and historical access

To enable logging of events and alarms, the "Database Horizon" property must be non-zero.

Concepts

An event is a record with the following primary fields:

  • Timestamp: the date and time of the event
  • Type: the type of the event
  • Source: the source of the event

The primary fields are treated as the unique key for event records. If a new event is created with the same Timestamp, Type, and Source as an existing event, the new event replaces the old event1.

The Type field defines which additional fields the event may contain. Since event types are organized in a hierarchy, each event type inherits the fields defined by its parent type.

The Source field defines the "location" where the event occurred. This field is used when real-time subscriptions and historical queries are filtered to only include event sources in specific sub-hierarchies.

1

If the Type is marked as Immutable, both the old and the new events are kept in the historian.