Example Listener

Publisher project

Single BOOL variables are used as triggers in the Publisher project:

• bSendMessage to send a message.
• bRaiseAlarm to set an alarm.
• bClearAlarm to cancel an alarm.
• bConfirmAlarm to confirm an alarm.

In addition there is an option to set the JSON attribute in order to send it with both messages.

Listener project

The Listener project contains a function block, FB_Listener, which extends the FB_ListenerBase function block contained in the Tc3_EventLogger. The function block implements the functions for receiving the messages:

• OnMessageSent: when a message has been sent the EventLogger will call this method as a callback. The method counts the number of messages.
• OnAlarmRaised/OnAlarmCleared/OnAlarmConfirmed: if the alarm changes its state the EventLogger will call this method as a callback. The methods count the number of state changes.
• To initiate receiving of messages, an Execute method is implemented at the function block.
• The text of the last received message can be retrieved.
• The function block FB_ListenerTest uses the FB_Listener. In doing so it registers the event class to be received once. Another event class that exists is not received to demonstrate the filter functionality.

Requirements