About Event Types, Categories, and Conditions
The OPC Classic Alarms and Events collector captures all event types, categories, sub-categories, and conditions sent to it by the OPC Alarms and Events server.
Event Types
Three basic types of events are sent by an OPC Alarms and Events server: Condition, Simple, and Tracking. Each of these types has its own categories, sub-categories, and conditions. For example, a Condition event may have a Level category, which itself may have several conditions, such as LO LO, LO, HI, and HI HI.
- Condition
- Condition events record the transition of states in an alarm. For example, a condition event could be recorded for an alarm when the level changes from LO to HI HI.
- Tracking
- Tracking events are not associated with conditions, but rather track activity between the OPC Alarms and Events server and an OPC client. For example, if an operator acknowledges an alarm, a tracking event is recorded.
- Simple
- Simple events record everything not covered by Condition or Tracking events. For example, if a device were to fail, a simple event would be recorded.
Event Categories
Event categories are used to group similar event types and are configured on the OPC Alarms and Events server. For example, you might set up categories for System Events, Process Events, and Batch Events. You might likewise set up categories for different areas of your process, such as Premix, Dry Mix, or Bake. Categories can hold multiple event types, and a given source can generate events for multiple categories.
Event Conditions
Conditions are named states of alarms and events within the OPC Alarms and Events server. Conditions can include LO LO, LO, HI, and HI HI, as well as SYSTEM_FAILURE, LIMIT EXCEEDED, NORMAL STATE, and others. Conditions may also contain sub-conditions, which help to narrow down the event conditions further. Refer to your OPC server documentation for a complete listing of its conditions.
For more information, refer to your OPC server documentation.