Detect Change

Detect change in signal value

  • Library:
  • Simulink / Logic and Bit Operations

    HDL Coder / Logic and Bit Operations

Description

The Detect Change block determines if an input signal does not equal its previous value. The initial condition determines the initial value of the previous input U/z.

Ports

Input

expand all

Input signal, specified as a scalar, vector, or matrix.

Data Types: single | double | int8 | int16 | int32 | uint8 | uint16 | uint32 | Boolean | fixed point | enumerated | built-in integer | floating point

Output

expand all

Output signal, true (equal to 1) when the input signal does not equal its previous value; false (equal to 0) when the input signal equals its previous value.

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

Parameters

expand all

Set the initial condition for the previous input U/z.

Programmatic Use

Block Parameter: vinit
Type: character vector
Values: scalar | vector
Default:'0'

Specify whether the block performs sample- or frame-based processing:

  • Columns as channels (frame based) — Treat each column of the input as a separate channel (frame-based processing).

    Note

    Frame-based processing requires a DSP System Toolbox™ license.

    For more information, see Sample- and Frame-Based Concepts (DSP System Toolbox).

  • Elements as channels (sample based) — Treat each element of the input as a separate channel (sample-based processing).

Use Input processing to specify whether the block performs sample- or frame-based processing. The block accepts frame-based signals for the input u. All other input signals must be sample-based.

Input Signal uInput Processing ModeBlock Works?
Sample basedSample basedYes
Frame basedNo, produces an error
Sample basedFrame basedYes
Frame basedYes

For more information about these two processing modes, see Sample- and Frame-Based Concepts (DSP System Toolbox).

Programmatic Use

Block Parameter: InputProcessing
Type: character vector
Values: 'Columns as channels (frame based)' | 'Elements as channels (sample based)'
Default: 'Elements as channels (sample based)'

Set the output data type to boolean or uint8.

Programmatic Use

Block Parameter: OutDataTypeStr
Type: character vector
Values: 'boolean' | 'uint8'
Default: 'boolean'

Block Characteristics

Data Types

Boolean | double | enumerated | fixed point | integer | single

Direct Feedthrough

no

Multidimensional Signals

no

Variable-Size Signals

yes

Zero-Crossing Detection

no

Extended Capabilities

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™.

Introduced before R2006a