Compare To Constant

Determine how signal compares to specified constant

• Library:

• Simulink / Logic and Bit Operations

  HDL Coder / Logic and Bit Operations

Description

The Compare To Constant block compares an input signal to a constant. Specify the constant in the Constant value parameter. Specify how the input is compared to the constant value with the Operator parameter.

Ports

Input

Port_1 — Input signal

scalar

Input signal, specified as a scalar, is compared with zero.The block first converts its Constant value parameter to the input data type, and then performs the specified operation.

Data Types: single | double | int8 | int16 | int32 | uint8 | uint16 | uint32 | Boolean | fixed point | enumerated | bus

Output

Port_1 — Output signal

0 | 1

The output is 0 if the comparison is false, and 1 if it is true.

Data Types: uint8 | Boolean

Parameters

Operator — Logical operator

<= (default) | == | ~= | < | >= | >

This parameter can have these values:

• == — Determine whether the input is equal to the specified constant.

• ~= — Determine whether the input is not equal to the specified constant.

• < — Determine whether the input is less than the specified constant.

• <= — Determine whether the input is less than or equal to the specified constant.

• > — Determine whether the input is greater than the specified constant.

• >= — Determine whether the input is greater than or equal to the specified constant.

Programmatic Use

Block Parameter: relop

Type: character vector

Values: '==' | '~='| '<' |'<='| '>='| '>'

Default: '<='

Constant value — Constant to compare with

constant

Specify the constant value to which the input is compared.

Programmatic Use

Block Parameter: const

Type: character vector

Value: scalar | vector | matrix | N-D array

Default: '3.0'

Output data type — Data type of the output

boolean (default) | uint8

Specify the data type of the output, boolean or uint8.

Programmatic Use

Block Parameter: OutDataTypeStr

Type: character vector

Values:'boolean' | 'uint8'

Default: 'boolean'

Enable zero-crossing detection — Select to enable zero-crossing detection

check (default) | uncheck

Select to enable zero-crossing detection. For more information, see Zero-Crossing Detection.

Programmatic Use

Block Parameter: ZeroCross

Type: character vector

Values: 'off' | 'on'

Default: 'on'

Model Examples

Illustration of Law of Large Numbers

Use MATLAB System blocks to illustrate the law of large numbers.

Open Model

Block Characteristics

Data Types	Boolean | double | enumerated | fixed point | integer | single
Direct Feedthrough	no
Multidimensional Signals	yes
Variable-Size Signals	yes
Zero-Crossing Detection	yes

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

HDL Code Generation

Generate Verilog and VHDL code for FPGA and ASIC designs using HDL Coder™.

For more information about HDL code generation, see Compare To Constant.

PLC Code Generation
Generate Structured Text code using Simulink® PLC Coder™.

Fixed-Point Conversion
Convert floating-point algorithms to fixed point using Fixed-Point Designer™.