Block Properties

The Block Properties window allows you to configure the functional properties of any block selected in a diagram. Double-click the block or choose [Diagram/Fault Tree] > Properties > Block Properties or Phase > Settings Block Properties, depending on the type of diagram you are working with, to open the Block Properties window.

You can also define the properties for multiple blocks simultaneously by selecting the blocks and then opening the Block Properties window. If different types of blocks are selected (e.g., standard and node), only the properties that apply to all selected blocks will be available in the Block Properties window. You cannot open the Block Properties window if there is an ambiguous selection (e.g., if you selected both standard blocks and containers).

Note: Double-clicking a subdiagram block will open the subdiagram that the block is based on. Open the Block Properties window for a subdiagram block by selecting the block and choosing the command on the Ribbon or pressing CTRL+E.

Regardless of the type of block you are working with, the Block Properties window always has the following elements:

Name and Description: Each block is given a default name that is determined based on the block type's default name format. You can type new text either instead of or in addition to the default name. The Name field must be populated. Description text is optional.

Note that an asterisk is used (*) to represent default block names. The block name that is displayed in the diagram will replace the asterisk with the block's default name; this allows the block name to be updated dynamically. For example, a node's default name indicates its k-out-of-n value. If you change the value in the node's Number of Paths Required field, the node's name will automatically update when you close the Block Properties window.

Display properties for the block name and description may be set in the Block Style window for the individual block or in the Diagram Style window for all blocks added to the diagram.

For standard blocks (including contained blocks) in RBDs and for events in fault trees, this area contains an Optimum Replacement icon. Click this to open the Optimum Replacement window for the current block; this window allows you to determine the most cost-effective time to replace the component based on costs for planned (i.e., preventive) and unplanned (i.e., corrective) replacement.

Identifiers: These fields allow you to enter additional information about the block, such as a part number, a revision number, keywords that apply to the block, etc.
Active Block: This drop-down list at the bottom of the Block Properties window allows you to specify another block in the diagram that you want to set the block properties for. This allows you to set the properties for multiple blocks without having to open and close the Block Properties window for each block. If you have made changes to the current block’s properties, when you change the active block, a window may appear asking if you want to apply the changes you made to the active block. This window will appear only if the Ask to apply changes when selecting different block in Properties window option is selected on the Other page of the Application Setup.
- Click Yes to apply the changes to the current active block and then change the active block.
- Click No to discard the changes to the current active block and then change the active block.
- Click Cancel to leave the current block active. Your changes will be neither applied nor discarded at this time.
Style opens the Block Style window, which allows you to customize the appearance of the active block.
Attachments allows you to attach related files to the block. Clicking this icon opens the Attachments window.

The other properties available will vary depending on the type of block you are working with. Consequently, these properties are documented in the sections relating to the block types.

For RBDs, the block types include:

Standard blocks represent some functional portion of the system, such as a component, subsystem, assembly or failure mode.
Node blocks allow you to construct k-out-of-n configurations. In these configurations, a specified number of paths must reach the node and the node must not fail in order for the system to be successful.
Subdiagram blocks represent existing diagrams. For example, you might have an RBD that models an assembly. You can use a subdiagram block to include that assembly in an RBD that represents a larger system.
Standby containers hold blocks that operate in a standby configuration, where one or more of the blocks in the container are active while one or more blocks are dormant (i.e., standby or quiescent). The dormant blocks are available to become active under specified circumstances. The blocks inside the container describe the characteristics of the items that operate together in the standby configuration.
Load sharing containers hold blocks that operate in a load sharing configuration. This indicates that two or more blocks in the container share the work. The blocks inside the container describe the characteristics of the items that operate together in the load sharing configuration. For example, you might have two blocks in a load sharing container in a configuration where the container must provide an output of 8 volts. If both blocks are operational and each is set to provide 50% of the load, then each block will provide an output of 4 volts. If one of the blocks fails, however, then the other block will have to provide the entire 8 volts of output.

For fault trees, the block types include:

AND gates: The output event occurs if all input events occur.
OR gates: The output event occurs if at least one of the input events occurs.
Voting OR gates: The output event occurs if some quantity (k) or more of the (n) input events occur.
NOT gates: The output event occurs if the input event does not occur, and vice versa. This gate performs inversion.
NAND gates: The output event occurs if any one of the input events does not occur.
NOR gates: The output event occurs only if none of the input events occur.
Inhibit gates: The output event occurs if all input events occur and an additional conditional event occurs.
Standby gates identify blocks that operate in a standby configuration. Events that are below a standby gate are dependent events, which describe the characteristics of the items that operate together in the standby configuration.
Load sharing gates identify blocks that operate in a load sharing configuration. Events that are below a load sharing gate are dependent events, which describe the characteristics of the items that operate together in the load sharing configuration.
Priority AND gates: The output event occurs if all input events occur in a specific sequence.
Sequence enforcing gates: Events are constrained to occur in a specific sequence and the output event occurs if all input events occur in that specified sequence.
Events are simply representations of some occurrence, typically a failure or error.
Subdiagram blocks represent existing diagrams.