If all rules on the rule queue are processed and the queue becomes empty, the scenario instance goes into a monitoring stage.

The scenario instance stays in this state until some external source changes a variable, block parameter or block field that is referred to in any condition of any of its rules. This can occur because of a user sending in a scenario modification, or a block changing its properties in response to some external event feed.

If this occurs, then the affected rules are added to the rule queue and processed in the order as described previously.

This process of placing rules on the rule queue and processing them continues until a rule condition is true and the corresponding action requests a state transition to another state. After moving to the new state, Event Modeler places the new rules on the queue and evaluates them. Rule processing stops only when there are no rules left to be evaluated.