Basic Concepts in Ansys Scade One Application — Lesson 1

Operators

Ansys Scade One software allows the user to design graphically with the help of operators, used to describe Low-Level Requirements (LLRs). There are four types of operators: predefined, user-defined, imported, and library operators. Predefined operators are located in the catalog after right-clicking, predefines operators include basic mathematical operations, bitwise, relational, boolean, array, structural, group, selection, time, arithmetic, and higher order operators.

User-defined operators are data flow equations comprised of predefined operators and other user-defined operators. Imported operators consist of external C codes that enhance the semantics of the Ansys SCADE software language. Library operators are user operators from another project, ready to be used. The following table presents the predefined operators and library operators utilized in this study.

Symbol	Name	Description
	Fold	A higher-order function to accumulate the result of the N operator applied to the collection of data in the input
	Scalar to Vector	Created an array of size Ns with each element having the value of the Scalar input
	Plus	Addition of the scalar inputs
	Polymorphic Division	Division with real inputs
	Strictly greater than	If the first input is greater than the second, the output is set to true
	Pre	Time-delay operator for an output value from 1 cycle in the past.
	Liblinear: Derivative	Output(k)= (u(k)-u(k-1))/TimeCycle
	Common: Abs value	Computes the absolute value of real or integer values.
	Map	A higher-order function that applies the * operator to each of the Ds-1 elements in the input collection by position.
	Reverse	Permutes values of an array
	Minus	Subtraction of the scalar inputs
	Slice	Extracts and arrays from the input array from its 2nd to its N-1 positions.
	If-then-else	If “true”, the first input is output, and if “false”, the second input is output
	Liblinear: Gain	Multiplies input by a factor k.
	Liblinear: Integral	Computes the integral of Input using the trapezoid rule
	Instance block	Implements a given function a,b => (a+b)/2

Data Types and Constants

The Ansys Scade Suite™ model-based development environment for critical embedded software language facilitates operations on a range of data types but also allows the definition of user types. There are three kinds of data types: user-defined, imported, and predefined. Predefined data types include integer, bool, float, and char. User-defined data types are considered in three different formats: equivalent data types, used to enhance model readability (for instance, Speed=float); enumerated data types (for example, color=enu {blue, green, red}); and structural data types, including data structures and arrays [3]. In this study, all variables or constants used have a predefined data type, which is float64.

Imported data types are used to define the data types in imported operators. Constants are utilized to input system-specific constant values along with their corresponding data types. Constant values that will be consistently used within a system are documented in this section, as depicted in the following Table. The use of named constants enhances the readability of the model.