FB_TcEventFilter

Provides the functionality to specify an event filter.

The filters are provided via a floating interface following a structured query language. It describes which messages should apply.

• Conditions can be linked through .AND_OP() and .OR_OP().
• Conditions can be negated through .NOT_OP.
• Conditions can be defined through properties such as .isAlarm() or .EventClass.EqualsTo(<EventClass>), for example. A complete list of properties can be found in the API documentation.
• A grouping can be formulated through .FilterExpression(<SubCondition>). The <SubCondition> itself is a FB_TcEventFilter or ITcEventFilter.

A filter is applied once it has been compiled. To receive messages it is assigned to a recipient via FB_ListenerBase2.subscribe(), for example. In this way FB_ListenerBase2 takes over the filter and provides a corresponding return value, which is described here. The filter can be amended by repeating FB_ListenerBase2.subscribe().

Sample

A filter can be assembled in the following way, for example:

fbFilter.Severity.GreaterThan (TcEVentSeverity.Error).AND_OP().Source.Name.Like('%Main%');

The Example filter illustrates the usage.

EtherCAT filter

The mechanism for receiving EtherCAT emergency messages is similar to that described above. The entry point in the chained method calls is .EtherCATDevice(), which first provides a direct query to ascertain if it was sent from an EtherCAT device (IsEtherCATDevice()). From here you can filter based on the manufacturer (.VendorId()), the product code (.ProductCode()) or the revision (.RevisionNo()).

Syntax

Definition:

FUNCTION_BLOCK FB_TcEventFilter IMPLEMENTS I_TcEventFilter, I_TcExpressionBase

Methods

Properties