Switches

In BlockSim, a standby container, priority AND gate or sequence enforcing gate can be configured as a switch that is necessary to transfer the activity from the active block to a standby block (and then back to the original active block, if the standby block later fails or if the original active block is set to be reactivated after repair). To do this, assign a switch resource to the container or gate. Switches are resources that can be shared among analyses and can be managed via the Resource Manager.

To assign a switch to a container or gate, you can either select an existing switch or create a new one. Click the Switch field and then click the arrow to display the Quick Switch Action Wizard. In the wizard, you can click Select Existing Switch to display a list of the available switches. You can also click Create New Switch to open the Switch window; in this window, define the properties of the switch, then click OK to create the new switch and apply it to the block.

Once a switch has been assigned to the block, you can view and/or edit its properties from the Switch Action Wizard by clicking the View/Edit icon.

You can remove the switch from the block by clicking the Remove icon in the Switch Action Wizard.

You can also add, change or edit the components of the switch (i.e., the model, corrective task, scheduled tasks and/or maintenance group) directly from the Switch field's subfields. Be aware that any changes you make here will apply everywhere that the switch is used.

Switch Window

The Switch window is divided into two areas: the Resources area allows you to define the switch's reliability and maintenance characteristics, while the Properties area allows you to define all remaining switch properties. By default, the Properties area is on the left side of the window and the Resources area is on the right side. You can click the Change Orientation icon to toggle the orientation of the areas between horizontal and vertical.

You can also display only one of the areas or both of the areas by using the following icons to move the splitter all the way to the left/top, to the center, or all the way to the right/bottom.

For a new resource, a name will be proposed automatically based on the default naming criteria established for the current database (see Default Name Formats window). You can replace this with your own name, if desired. Remember that the name and identifiers are the primary way in which your team will be able to find the resources you need for your analyses.

In the Properties area, the following properties are available to configure the switch:

  • Switch Action
    • Probability per Request allows you to specify the probability that the switch action will succeed the first time it is needed. This also applies to the switch back to the original active block, if any.
    • Delay Time allows you to specify the amount of time it takes to perform the switch each time it happens. This includes the time for the first switch and any restarts, if applicable. You must specify the units used.
    • Allow Restarts if selected, indicates that if the switch fails on the first start, there will be attempts to restart the switch. If this option is selected, you must specify the Number of Restarts allowed. If the switch is not successful by the last specified restart, then it is considered to be failed. In the Switch Restart Probability field, specify the likelihood that the switch will succeed when you attempt to restart after an initial failure. This value is specified as a decimal, where 1 indicates a 100% probability of success.
    • Switch operates even if the system is down if selected, indicates that the switch continues to operate even if the system is not operating. If not selected, indicates that the switch will not continue to accumulate age.

  • History provides information about when the record was created and last updated. If the history log has been activated at the project level, you can click the View Item History icon to open the Record History Log for the record.

  • Trace Usage. For existing resources, the link at the bottom of the window indicates how many times the resource is currently being used. If you need more information, click the link or the icon to open the Dependency Viewer.

The Resources area allows you to specify the reliability and maintenance properties of the switch, including the model that represents the reliability of the switch itself (either a reliability model, a probability of failure model or an event occurrence model), any tasks that apply to the switch and the maintenance group that it is associated with, if any. The maintenance information in this area is applicable only when the switch is used in a simulation diagram. If the Switch window is accessed from within an analytical diagram, the maintenance-related fields (i.e., those pertaining to tasks and to maintenance groups) will not appear even if the switch has maintenance properties.

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