|Program customized run-time errors and warnings|
|Return past value of operand|
|Return time derivative of operand|
|Define component equations|
|Reuse expressions in component equations and in member declarations of domains and components|
|Perform time integration of expression|
|Define intermediate terms for use in equations|
|Return value based on interpolating set of data points|
|Convert variable or parameter to unitless value with specified unit conversion|
- Defining Component Equations
The purpose of the equation section is to establish the mathematical relationships among a component’s variables, parameters, inputs, outputs, time and the time derivatives of each of these entities. The equation section of a Simscape™ file is executed throughout the simulation.
- Simple Algebraic System
This example shows implementation for a simple algebraic system.
- Use Simulation Time in Equations
This example shows how you can access global simulation time from the equation section.
- Using Conditional Expressions in Equations
You can specify conditional equations by using
- Using Intermediate Terms in Equations
Textbooks often define certain equation terms in separate equations, and then substitute these intermediate equations into the main one. For example, for fully developed flow in ducts, the Darcy friction factor can be used to compute pressure loss:
- Using Lookup Tables in Equations
You can use the
tablelookupfunction in the
equationssection of the Simscape file to interpolate input values based on a set of data points in a one-dimensional, two-dimensional, or three-dimensional table. This functionality is similar to that of the Simulink® and Simscape Lookup Table blocks. It allows you to incorporate table-driven modeling directly in your custom block, without the need of connecting an external Lookup Table block to your model.
- Programming Run-Time Errors and Warnings
assertconstruct to implement run-time error and warning messages for a custom block. In the component file, you specify the condition to be evaluated, as well as the error message to be output if this condition is violated. When the custom block based on this component file is used in a model, it will output this message if the condition is violated during simulation. The optional
Actionattribute of the
assertconstruct specifies whether simulation stops when the predicate condition is violated, continues with a warning, or ignores the violation.
- Initial Equations
Specify additional equations to be executed during model initialization only.
- Simscape Functions
Use Simscape functions to reuse expressions in equations and member declarations of multiple components.
- Import Symbolic Math Toolbox Equations
Example of using Symbolic Math Toolbox™ software to solve the physical equations, generate code in the format appropriate for the Simscape language equation section, and incorporate the generated code into the equation section of a component file.