Page 177 - ExtendSim User Guide
P. 177

Queueing 151
Advanced queue topics
This block is especially useful for making sure that items have a particular characteristic at a specific time. For instance, you would use this queue to reassemble parts in the correct order or to insure that subassemblies are correctly matched with each other.
☞ For more detail, please see the Queue Matching online help by clicking the “Help” button in the lower left of the block’s dialog.
Queue Matching model
In the following example, electronic systems arrive from the field, are separated into their indi- vidual components for refurbishing, and are reassembled. In this operation, all of the compo- nents but only 40% of the housings need to be reworked. In addition, it is important that the housings for each system be reassembled with their original (refurbished) component set.
Queue Matching model
The Information block counts each electronic system as it arrives and outputs the total number that have passed through the block. The Set block uses this value to set a Serial Number attri- bute for each electronic system. After refurbishment, the system is reassembled using its origi- nal parts.
Other models that use the Queue Matching block
The folder Examples\Discrete Event\Queue Matching contains additional models that use the Queue Matching block. Those models explore more advanced topics such as modeling fixed and variable requirements for specific items.
Advanced queue topics
This section discusses viewing, initializing, and animating the contents of a queue. These tech- niques are useful in creating a more exact model as well as for debugging and/or validating a model.
Viewing and manipulating queue contents
Although the Queue itself has a Contents tab that can show and report the items within the Queue at any time (See “Item Contents of queues and activities” on page 716), a powerful ExtendSim feature is the ability to also manipulate the contents of a queue. The Queue Tools block (Utilities library) allows you to view items in a queue, manually manipulate the ordering of those items, and initialize the queue’s contents. To use this block, connect from the L (length) output of a Queue or Queue Equation block to the value input connector of a Queue Tools block. The block has two tabs, View and Options, as discussed in the following sections.
View tab of Queue Tools block
The Queue Tools block’s View tab is used to manipulate items in a Queue or Queue Equation block and display information about the items. When the model is run, every item in the attached queue will have an entry in the table.
Discrete Event


































































































   175   176   177   178   179