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Miscellaneous 437
Global and advanced options in the Executive
suggested that you do not change the default setting unless you have an excellent reason to do so.
Update flow status
In the Rate library, some values change continuously over time. The frequency of updating those values can be customized by setting options for the Convey Flow, Diverge, Interchange, Merge, Tank, and Valve blocks. They define how often the following information is updated:
• Thelevelofflowinresidenceblocks(ConveyFlow,Interchange,andTank)
• TheamountofflowpassingthroughtheConveyFlow,Diverge,Interchange,Merge,Tank, and Valve blocks
At a minimum, the discrete rate global system
updates flow status only when it needs to. The
updating options provide two additional oppor- Valve’s default update setting
tunities to have calculations performed. The
option that has been selected in the Executive is displayed in each block’s Options tab (shown in the screenshot), along with any choices associated with that option. The choices in the popup menu are:
• Only when necessary. This default setting is computationally the most efficient option because flow status is updated only when needed by the system. With this setting, the infor- mation is updated:
• WhenablockisdeterminedtobepartofanLParea
• Whenever a block creates an internal event such as reaching a new indicator • When a block receives an active message at one of it value output connectors
• Each block defines how often. If this option is selected, each block’s Options tab will give you the choice to check the option Update animation and results at each event. If that is checked, the calculation of the flow status will occur at each step for that block.
• Eachblockateachstep.Withthischoice,everyblockwillupdateateachstep.Thisoption has to be used cautiously because it is computationally demanding to update the information this frequently.
Valve animates and reports blocking and starving information
This option only affects the animation and reporting of Valve blocks. A Valve can be limiting, not-limiting, blocked, starved, or blocked and starved. By default, the Valve’s Results tab and S (status) output connector only report whether the block is limiting (0) or not limiting (1). The Results tab also reports cumulative information regarding the percentage of time the block was limiting or not limiting.
When the global option is checked, the block’s Results tab and its S output report all status information as a value:
• limiting (0)
• starved (1)
• blocked (2)
• starvedandblocked(3)
Discrete Rate

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