Page 157 - ExtendSim User Guide
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Items, Properties, and Values 131
Item properties
attribute by name from the list in the attribute popup menu in an attribute-reading block, such as the Activity or Get block.
Activity or Workstation blocks
In the dialog of an Activity or Workstation block, you can specify that an item's attribute value be used as its processing time, as shown below.
Get block
When items pass through the Get block, it accesses information about the attributes that have been specified in the table in its dialog. It then reports the information in the table and on its value output connectors. What the Get block reports and where, depends on the type of attri- bute:
• Valueattributes.ThevaluefortheattributeispostedintheValuecolumnoftheattribute table and on the value output connector that corresponds to the attribute.
• Stringattributes.ThestringtextisdisplayedintheValuecolumnoftheattributetableand the number that corresponds to the string is posted on the appropriate value output connec- tor.
☞ Connecting a Lookup Table block (Value library) that is set to Lookup the: input value to a Get block that accesses a string attribute will cause the strings for that attribute to appear as a popup list in the Lookup Table block’s left most column.
• DB Address attributes. You can get either an individual element of a database address or its entire address. To do this, from the popup menu in the table’s “DB attrib reports” column, select which of the 5 components will be retrieved (db index, table index, field index, record index, or db address). The first 4 choices provide individual elements of the address; the “db address” choice provides the entire address. The information will be reported in the Value column and on the value output connector for that attribute.
☞ To access all five elements of a DB address attribute, add five rows to the table. Each row should have the same DB address attribute listed in the Property Name column, but different selections for the “DB attrib reports” column. This comes in handy when the Get block is working in conjunction with the Read or Write blocks (Value library). It allows the read or write location to vary based on what information is traveling on the item.
In addition to value outputs for reporting an attribute’s value, the Get block has a  (delta) con- nector for reporting when an attribute’s value changes. The  connector outputs a 1 when an item's attribute value (for the first attribute specified in the dialog) differs from the previous item's attribute value. Otherwise it outputs 0. This is useful for determining when there is a new type of item or when an attribute value used for processing time has changed. For exam- ple, you can have an attribute called “Type” with values that specify the type of item. When the value of Type changes, indicating a new type of item, the  connector outputs 1. This is shown in “Adding setup time” on page 186.
Discrete Event

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