Page 646 - ExtendSim User Guide
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620 Presentation
Hierarchy
• Hierarchical blocks can be copied to other areas of the model or to other models and used just like other blocks.
• The settings within a hierarchical block can be changed by double-clicking the hierarchical block, then double-clicking the desired block’s icon, or by changing the desired block’s cloned dialog items.
• Hierarchicalsubmodelwindowsaresimilartomodelwindows:addblocksfromalibrary, create hierarchical blocks, add graphics, type labels and other text, clone dialog items onto them, and so forth.
• The components of a hierarchical block (icon, connectors, or Help text) can be changed by accessing the hierarchical block’s structure window.
• Unlikeotherblocks,bydefaulthierarchicalblocksaresaveddirectlyinthemodelascopies. This characteristic allows them to be treated much like a copy of a portion of the model. You can copy a hierarchical block to another part of your model and make changes to its sub- model window without affecting the original hierarchical block. This is known as physical hierarchy.
• Youcanchoosetosaveahierarchicalblockinalibrary,inwhichcaseitcanbetreatedmuch like a regular block. When you make changes to the hierarchical block’s structure window and you also choose to update all instances of that block, it is known as pure hierarchy.
Important notes about hierarchical blocks
☞ The action of creating a hierarchical block cannot be undone. If you accidentally include more blocks than intended in the hierarchical block, remove them from the block’s submodel and put them back into the model using the Cut and Paste commands in the Edit menu.
☞ Named connections (discussed on page 638) only connect within one level in a hierarchical model. This means that the data will not flow between levels if you have a named connection on one level and a corresponding named connection in a block at a lower or higher level. To connect between hierarchical levels, use the Throw and Catch blocks in the Value, Item, or Rate libraries, or add connectors to hierarchical blocks. To see how Throw and Catch blocks are used with hierarchy, see “Throw Item and Catch Item blocks for merging item streams” on page 160. For more information on adding connectors to hierarchical blocks, see “Step 4: Add connectors” on page 623.
☞ By default a hierarchical block is saved only in the model. To save it in a library, use the Save Block As command, described later in this topic.
Although the blocks within hierarchical blocks (see “Hierarchy” on page 618) are automati- cally updated if they are changed in a library, because hierarchical blocks themselves are sub- models and contain both blocks and data, hierarchical blocks saved in a library will not automatically update their corresponding hierarchical blocks in a model as that might change the existing data in the model.
Because they can contain entire submodels, hierarchical blocks can become quite large. Librar- ies have a 15MB limit, so you may need to use more than one library to store all the hierarchi- cal blocks for a model.
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