Page 769 - ExtendSim User Guide
P. 769

Data Management and Exchange 743
User interfaces for data exchange
Link dialog checkboxes
Outside of a simulation run, blocks receive messages whenever dynamically linked data changes at the source. To maximize simulation speed you may not want these update messages sent during certain phases of a run. As shown on page 739 and page 740, when the Database Table or Global Array option is selected in the Link dialog, the dialog displays four check- boxes:
• Init messages
• Simmessages
• Final messages
• Read-Onlylink
These allow you to control the link’s data update behavior, as discussed below.
The first three link options (Init messages, Sim messages, and Final messages) control whether or not blocks receive update messages when linked values change during specific points in a simulation run. For example, the “Init messages” option determines whether a block receives a message if a linked value changes during the InitSim message.
These three options default to on. Turning an option off prevents ExtendSim from sending data update messages to the linked blocks if the data source is updated during that phase of the sim- ulation. For example, if you know the dynamic link only updates during the FinalCalc mes- sage, it will reduce the messaging and speed up the simulation to turn off the Init messages and Sim messages options.
When the Init messages and Final messages options are turned on, linked blocks will receive an additional message during InitSim and/or FinalCalc, causing an update of the linked dialog items during those phases.
The fourth checkbox is the Read-Only link option, which is off by default. If checked, the linked data can only be changed from the data structure side. In that case, you will not be allowed to edit the parameter or the data table directly and the live link is only one-way (from the internal structure to the data table or parameter.
Use these options carefully, since they can dramatically change linking behavior. You would probably only want to uncheck a message option (Init messages, Sim messages, or Final mes- sages) if you are sure that the source data won’t change during that message.
Finding linked dialog items
The command Edit > Open Dynamic Linked Blocks opens the Find Links dialog, shown on the right. This is use- ful for examining and locating linked dialog items.
The options in the dialog allow you to
selectively choose which types of links
you want to open. Choosing Database
links, Global Array links, or Dynamic
Array links will specify whether or not
those types of links are located. The
User-Defined links checkbox deter-
mines whether to locate the links defined by the user through the user interface or (if the check-
Link dialog for Global Array
How To

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