Process blockages are modelled by Threshold objects that open and close according to various types of rules:
· TimeSeriesThreshold. Opens and closes when the value provided by a TimeSeries object meets various conditions.
· ExpressionThreshold. Opens and closes according to a specified expression that returns TRUE or FALSE (given by the values 1 and 0, respectively).
· SignalThreshold. Opens and closes when an entity is received by an EntitySignal object.
All types of Threshold objects share the following inputs and outputs.
Threshold Inputs
Keyword |
Description |
OpenColour |
The colour of the threshold graphic when the threshold is open. |
ClosedColour |
The colour of the threshold graphic when the threshold is closed. |
ShowWhenOpen |
A Boolean value. If TRUE, the threshold is displayed when it is open. |
ShowWhenClosed |
A Boolean value. If TRUE, the threshold is displayed when it is closed. |
Threshold Outputs
Output Name |
Description |
UserList |
The objects that are stopped by this Threshold. |
Open |
If open, then return TRUE. Otherwise, return FALSE. |
OpenFraction |
The fraction of total simulation time that the threshold is open. |
ClosedFraction |
The fraction of total simulation time that the threshold is closed. |
OpenCount |
The number of times the threshold's state has changed from closed to open. |
ClosedCount |
The number of times the threshold's state has changed from open to closed. |
The response of an object to the closure of one of its Thresholds depends on which one of the following keywords was used.
Keywords that accept Thresholds
Keyword |
Description |
ImmediateThresholdList |
A list of thresholds that must be satisfied for the object to operate. Operation is stopped immediately when one of the thresholds closes. If a threshold closes part way though processing an entity, the work is considered to be partly done and the remainder is completed once the threshold re-opens. |
ImmediateReleaseThresholdList |
A list of thresholds that must be satisfied for the object to operate. Operation is stopped immediately when one of the thresholds closes. If a threshold closes part way though processing an entity, the work is interrupted and the entity is released. |
OperatingThresholdList |
A list of thresholds that must be satisfied for the object to operate. If a threshold closes part way though processing an entity, the remaining work is completed and the entity is released before the object is closed. |
ReleaseThresholdList |
A list of thresholds that must be satisfied for the object to operate. If a threshold closes part way though processing an entity, the remaining work is completed, but the entity is retained until the threshold re-opens. |
A given Threshold can appear in only one of these keywords at a time. A single Threshold can be used by multiple objects.