Using Event Analysis Flowcharts

Event analysis flowcharts (formerly RENO flowcharts) are used to build models of probabilistic or deterministic problems, processes or scenarios in order to help you understand and/or quantify them. The flowchart is a graphical representation of the mathematical process of predicting an outcome.

The example that follows demonstrates some of the basic techniques used in working with event analysis flowcharts. This simple flowchart generates failure times for 10 items.

1. Add diagram

Right-click the Event Analysis Flowcharts folder in the current project explorer and choose Add Event Analysis Flowchart.



2. Define resources
   1. Create a variable

   This resource will control the number of items to generate failure times for.

   Choose Home > ReliaSoft > Resource Manager.

   

   In the Resource Manager, choose Variables and then choose Home > Edit > Add.

   

   Define the variable properties. (See Variables.)

   

   2. Create a model

   This resource will define the model used to generate the failure times.

   In the Resource Manager, choose Models and then choose Home > Edit > Add.

   Define the model properties. (See Models.)

   

3. Add blocks (See Flowchart Block Types.)
   1. Add a standard block (to increment the variable)

   This block will increment the value of the Number_of_Items variable.

   Right-click inside the diagram and choose to add a standard block. (See Flowchart Standard Blocks.)

   

   To edit the block's properties, right-click it and choose Block Properties.

   Click inside the Equation field and type Number_of_Items + 1. (For additional tools to assist with building equations, see Function Selector and Equation Editor.)

   

   Click inside the Storage Variable field and select the Number_of_Items variable.

   

   2. Add a conditional block (i.e., create an IF statement)

   This block will determine the simulation path based on whether the item count has reached 10.

   Right-click inside the diagram and choose to add a conditional block. (See Conditional Blocks.)

   In the block's properties window, specify that if the incoming value is less than or equal to 10, a value of 0 will be passed on the "true" path. Otherwise, a value of 0 will be passed on the "false" path.

   

   3. Add a standard block (to generate the failure times)

   This block will generate a failure time by returning a random value based on the Item_Failure_Distribution model.

   In the block's properties window, right-click inside the Equation field, choose Show Function Selector then choose Event Analysis Internal Functions from the drop-down list. Double-click the rvm function.

   

   In the Enter Parameters window that appears, right-click in the Model field and open the Function Selector. Double-click the Item_Failure_Distribution model.

   

   4. Add a result storage block

   This block will store an array of the failure times generated by the standard block.

   Right-click inside the diagram and choose to add a result storage block. (See Result Storage Blocks.)

   In the block's properties window, specify that it will store an array of results.

   

   5. Create a FOR loop

   These blocks will form a loop that will cycle through the flowchart until the variable value reaches 10.

   Add a flag marker block, a go-to-flag block and a stop flag.

   Define the properties. (See Flag Marker and Go-to-Flag Blocks and Stop Flags.)

   

   

   

4. Connect blocks

Connect the blocks as shown below. To create each connection, hold down the ALT key, click the source block and drag a line to the destination block.



The first connector you create from the conditional block will be marked as the "true" path and the second as the "false" path. If necessary, you can switch these designations by right-clicking the connector and choosing Set to Failure or Set to Success on the shortcut menu.



5. Simulate the flowchart

Click the Simulate icon on the control panel.



Specify to run a single simulation with a seed of 1 and click Simulate. (See Flowchart Simulation Window.)



6. View the simulation results

From within the Flowchart Simulation Window, click Details. If you have closed the window, click the Results valid as of field on the diagram control panel.



To view the failure times generated during the simulation, click the result storage block in the navigation panel.



7. View plots

Click the Plot icon on the diagram control panel to open the plot sheet. (See Flowchart Plots for available plot types.)



On the plot sheet control panel, choose the plot type, then select the result storage block(s) to show in the plot.

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