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Tips and Techniques 313
Item library blocks
calculates the time from when items were first created to when they finish being primed. This includes the time items wait in the Queue.
Using a Set or Equation(I) and Information blocks
If you are tracking the item from some place other than its creation point, put a Set or Equa- tion(I) block at the beginning of the section you want to observe, create a new value attribute in that block, and set the attribute to the current time. Then place an Information block at the end of the section and enter the name of that attribute as the Timing attribute in its dialog.
In the example at right, an attribute named CycleTime2 has been created in the Set block. The Simulation Vari- able block (Value library) outputs current time and is attached to the Set block’s value input connector. For this model, the Information block calculates just the time that the items take to go through the priming and drying processes.
Item library blocks
Executive block
Cycle Time 2
The Executive block controls and performs event scheduling for discrete event and discrete rate models. An Executive block must be placed to the left of all other blocks in a discrete event or discrete rate model. Using it in a model changes the timing from continuous to dis- crete, and simulation time advances when events occur, rather than periodically.
This block can be used to:
• Manuallycontrolwhenthesimulationstops.Thedefaultisthatasimulationstopsattheend time set in the Run > Simulation Setup dialog. You can also choose to stop the simulation when the number at the Executive’s count input reaches a specified value.
• Allocateitemavailability.Toconservememory,thisnumbershouldbesomethingcloseto and less than the maximum number of items that you expect to see in the simulation. The default is that 10,000 items are initially available and additional items are made available in batches of 10,000.
• Declare and manage string attributes for items in Item library blocks.
• AtableintheItemAttributestabisusedtoenteradescriptivetextlabel(string)for each potential attribute value for a selected string attribute. For more information, see “Creating a string attribute” on page 115 and “Item attribute types” on page 126.
• OthertablesintheItemAttributestaballowyoutoselectanattributeforrenamingor deleting, and display blocks that use the selected attribute.
• Declare and manage string attributes for flow in Rate library blocks
Discrete Event

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