Periodic sample time constraint
Option to specify constraints on model sample times
Model Configuration Pane: Solver
Description
You can specify constraints on sample times for simulations that use a fixed-step solver. When the model does not satisfy the specified constraint, the software issues a diagnostic.
Dependencies
To enable this parameter, set the solver Type to Fixed-step
.
Settings
Unconstrained
(default) | Ensure sample time independent
| Specified
Unconstrained
The software imposes no constraints on sample times in the model.
When you select this option, the software assigns priority
40
to the sample time that corresponds to the fixed step size for the simulation. The software increments or decrements from40
to assign priorities to other rates in the model according to the value of the Higher priority value indicates higher task priority parameter. Continuous sample times always have the highest priority.When you select
Unconstrained
, you can configure these parameters:Fixed-step size (fundamental sample time)
Treat each discrete rate as a separate task
Higher priority value indicates higher task priority
Automatically handle rate transitions for data transfers
Ensure sample time independent
When you select this option, referenced models inherit sample time from the context in which they are used. Select this option to detect sample time problems related to referencing models with intrinsic sample time inside triggered or iterator subsystems.
The software checks to ensure that this model can inherit its sample times from a model that references it without altering its behavior. Models that specify a fixed step size cannot satisfy this constraint.
Specified
The software checks to ensure that the model operates at a specified set of prioritized periodic sample times. When you select this option, you must specify properties for each sample time you use in the model. The software issues a diagnostic when the model uses a sample time that is not specified. During simulation, higher priority tasks run first and can interrupt lower priority tasks as needed. Use the Sample time properties parameter to specify the rates and priorities for sample times in the model.
For information about how to use this option for multitasking models, see Tasking Modes and Execution Order (Simulink Coder).
When you select
Specified
, you can configure these parameters:Sample time properties
Treat each discrete rate as a separate task
Higher priority value indicates higher task priority
Automatically handle rate transitions for data transfers
Recommended Settings
The table summarizes recommended values for this parameter based on considerations related to code generation.
Application | Setting |
---|---|
Debugging | No impact |
Traceability | No impact |
Efficiency | No impact |
Safety precaution |
|
Programmatic Use
Parameter: SampleTimeConstraint |
Value: 'unconstrained' | 'STIndependent' | 'Specified' |
Default: 'unconstrained' |
Version History
Introduced before R2006a