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Verifying Information model
The example shown at the right illustrates the use of the History block to verify that batches are created at the correct time with the correct number of items.
The topmost Create block (labeled Schedule Batches) schedules when the batch is created and the Queue’s length (L) output deter- mines the batch size. This causes all items within the Queue to be batched.
Statistics and Model Metrics 299
Using the Item Log Manager to get item information
Verifying Information model
Using the Item Log Manager to get item information
The Item Log Manager (ILM) block (Item library) tracks how items change states during a run by doing two things:
1) During the simulation run, it directs other blocks in the model to collect data on items as they pass through. These “remote” data collecting blocks include History, Activity, Queue, Queue Equation, and Resource Item. Each of these blocks can be remotely instructed to collect specific item property information for the ILM through its “Data Collection” tab.
2) Oncetheremoteblockshavecollectedthedata,theILMpackagesitintoareport.Youcan control which types of data are included in the report and the order in which the data appears. This is done on the ILM block's “Configure Log” tab.
Once the run is complete, any number of reports can be generated from the data that has been collected in the remote blocks. These reports can be generated after each run either automati- cally or manually. You can have one or more ILM blocks in a model with each one responsible for generating its own report. The ILM also supports generating reports across multiple runs.
See the “Air Freight with Item Log” model for an example of using item logging. Also see the help of the Item Log Manager block for a detailed example showing how it works.
Accumulating data
There are various methods you can use to accumulate data. Attributes can be used to hold cumulative values, such as the total weight of an assembly or the number of parts in a box. And the Holding Tank block (Value library) can accumulate total processing time to determine equipment refurbishment schedules. Data can be accumulated at any step in the model, even when the item is not being processed.
It is important to not make the error of assuming that you can combine attribute values and then accumulate them. See “Using the Holding Tank block to accumulate values” on page 310 for more information.
Non-Processing model
In the Non-Processing model, one part from Stock and another from Manufacturing are com- bined into an assembly. The stock part weighs 10 pounds and the manufactured part weighs
Discrete Event

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