The Diagram consists of the following main items: 

States – A logical representation for the condition of a component or system.

    Emrald_State.png
  • Types
    • Start – the beginning state when simulation begins (one or more)
    • Standard – a normal state representing no special conditions
    • Key State – marks a state of interest, to be tracked and reported if in this state at the end of a simulation.  (All "End Sates" from traditional PRA should have a corresponding "Key State")
    • Terminal – user-defined simulation stopping point
  • Immediate Actions Section – actions taken when a new state is entered
  • Event/Action Section – events to look for when in this state and what action to take if the event is triggered

Actions – Actions are executed when entering a state or are performed when an event is triggered.

    Emrald_Action_1.png Emrald_Action_2.png
  • Transition – Start, exit, or move to a new state or states. Indicated by arrows on the diagram.  Can be probabilistic if moving to more than one state.
  • Change Value – Adjusts the value of a variable.
  • External Communication – Send a message to an external code such as a 3D simulation.
  • Execute Application – Runs a user defined script. Starts up an executable with the results of that script. Runs a second user defined script to post process any results from the executable and adjusts current states according to results of the script.

Events – Monitor for specified criteria and have one or more actions that are executed when that criteria is met.

    Time Based Event Types

    • Timer Event – monitors the current time against a time of interest.
    • Fail Rate Event – uses the sampling of a given failure rate to determine the execution time

    Condition Based Event Types

    • State Change Event – monitors when entering or exiting a specified state to determine the execution point
    • Component Logic Event – evaluates a logic model of component diagrams to determine execution point
    • Variable Condition Event – monitors variable values with user-defined code to determine execution point
    • External Sim Event – links to an external simulation flag to determine execution point