Logical Operator

Perform specified logical operation on input

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    Simulink / Logic and Bit Operations

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    HDL Coder / Logic and Bit Operations

  • Logical Operator block

Description

The Logical Operator block performs the specified logical operation on its inputs. An input value is true (1) if it is nonzero and false (0) if it is zero.

You select the Boolean operation connecting the inputs with the Operator parameter list. If you select rectangular as the Icon shape property, the name of the selected operator displays on the block icon. If you select distinctive as the Icon shape property, the name of the selected operator does not display on the block icon. This table shows supported operations:

OperationDescription

AND

TRUE if all inputs are TRUE

OR

TRUE if at least one input is TRUE

NAND

TRUE if at least one input is FALSE

NOR

TRUE when no inputs are TRUE

XOR

TRUE if an odd number of inputs are TRUE

NXOR

TRUE if an even number of inputs are TRUE

NOT

TRUE if the input is FALSE

If you select distinctive as the Icon shape, the block appearance indicates its function. Simulink® software displays a distinctive shape for the selected operator, conforming to the IEEE® Standard Graphic Symbols for Logic Functions.

To specify the number of input ports, use the Number of input ports parameter. The output type is specified using the Output data type parameter. An output value is 1 if TRUE and 0 if FALSE.

Note

The output data type should represent zero exactly. Data types that satisfy this condition include signed and unsigned integers, and any floating-point data type.

The size of the output depends on input vector size and the selected operator:

  • If the block has more than one input, any nonscalar inputs must have the same dimensions. For example, if any input is a 2-by-2 array, all other nonscalar inputs must also be 2-by-2 arrays.

    Scalar inputs are expanded to have the same dimensions as the nonscalar inputs.

    If the block has more than one input, the output has the same dimensions as the inputs (after scalar expansion) and each output element is the result of applying the specified logical operation to the corresponding input elements. For example, if the specified operation is AND and the inputs are 2-by-2 arrays, the output is a 2-by-2 array whose top left element is the result of applying AND to the top left elements of the inputs, and so on.

  • For a single vector input, the block applies the operation (except the NOT operator) to all elements of the vector. The output is always a scalar.

  • The NOT operator accepts only one input, which can be a scalar or a vector. If the input is a vector, the output is a vector of the same size containing the logical complements of the input vector elements.

When configured as a multi-input XOR gate, this block performs an addition modulo two operation as mandated by the IEEE Standard for Logic Elements.

Ports

Input

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First input signal, specified as a scalar, vector, or matrix.

Data Types: half | single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point

Second input signal, specified as a scalar, vector, or matrix.

Data Types: half | single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point

Nth input signal, specified as a scalar, vector, or matrix.

Dependencies

To enable additional input ports, use the Number of input ports parameter.

Data Types: half | single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point

Output

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Output signal, consisting of zeros and ones, with the same dimensions as the input. You control the output data type with the Require all inputs and output to have the same data type and Output data type parameters.

Data Types: half | single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point

Parameters

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Main

Select the logical operator to apply to block inputs.

  • AND — T if all inputs are TRUE

  • OR — TRUE if at least one input is TRUE

  • NAND — TRUE if at least one input is FALSE

  • NOR — TRUE when no inputs are TRUE

  • XOR — TRUE if an odd number of inputs are TRUE

  • NXOR — TRUE if an even number of inputs are TRUE

  • XOR — TRUE if the input is FALSE

Programmatic Use

Block Parameter: Operator
Type: character vector
Values: 'AND' | 'OR' | 'NAND' | 'NOR' | 'XOR' | 'NXOR' | 'NOT'
Default: 'AND'

Specify the number of block inputs as a positive integer.

Programmatic Use

Block Parameter: Inputs
Type: character vector
Values: positive integer
Default: '2'

Dependencies

This parameter is not available when you set the Operator to NOT.

Specify the shape of the block icon.

  • rectangular — Results in a rectangular block that displays the name of the selected operator.

  • distinctive — Use the graphic symbol for the selected operator as specified by the IEEE standard.

Programmatic Use

Block Parameter: IconShape
Type: character vector
Values: 'rectangular' | 'distinctive'
Default: 'rectangular'

Specify the sample time as a value other than -1. For more information, see Specify Sample Time.

Dependencies

This parameter is not visible unless it is explicitly set to a value other than -1. To learn more, see Blocks for Which Sample Time Is Not Recommended.

Programmatic Use

Block Parameter: SampleTime
Type: character vector
Values: scalar or vector
Default: '-1'

Data Type

To require that all block inputs and the output have the same data type, select this check box. When you clear this check box, the inputs and output can have different data types.

Programmatic Use

Block Parameter: AllPortsSameDT
Type: character vector
Values: 'off' | 'on
Default: 'off'

Specify the output data type. When you select:

  • boolean — The block output has data type boolean.

  • Inherit: Logical (see Configuration Parameters: Optimization) — The block uses the Implement logic signals as Boolean data configuration parameter to specify the output data type (see Implement logic signals as Boolean data (vs. double)) .

    Note

    This option supports models created before the boolean option was available. Use one of the other options, preferably boolean, for new models.

  • fixdt(1,16) — The block output has the specified fixed-point data type fixdt(1,16).

    Tip

    Click the Show data type assistant button to display the Data Type Assistant, which helps you set the data type attributes. For more information, see Specify Data Types Using Data Type Assistant.

  • <data type expression> — The block output has the data type you specify as a data type expression, for example, Simulink.NumericType.

    Tip

    To enter a built-in data type (double, single, int8, uint8, int16, uint16, int32, or uint32), enclose the expression in single quotes. For example, enter 'double' instead of double.

Programmatic Use

Block Parameter: OutDataTypeStr
Type: character vector
Values: 'Inherit: Logical (see Configuration Parameters: Optimization)' | 'boolean' | 'fixdt(1,16)' | '<data type expression>'
Default: 'boolean'

Model Examples

Modeling a Fault-Tolerant Fuel Control System

Modeling a Fault-Tolerant Fuel Control System

Combine Stateflow® with Simulink® to efficiently model hybrid systems. This type of modeling is particularly useful for systems that have numerous possible operational modes based on discrete events. Traditional signal flow is handled in Simulink while changes in control configuration are implemented in Stateflow. The model described below represents a fuel control system for a gasoline engine. The system is highly robust in that individual sensor failures are detected and the control system is dynamically reconfigured for uninterrupted operation.

Open Model
Friction Model with Hard Stops

Friction Model with Hard Stops

Model friction one way in Simulink®. The two integrators in the model calculate the velocity and position of the system, which is then used in the Friction Model to calculate the friction force.

Open Model
Building a Clutch Lock-Up Model

Building a Clutch Lock-Up Model

Use Simulink® to model and simulate a rotating clutch system. Although modeling a clutch system is difficult because of topological changes in the system dynamics during lockup, this example shows how Simulink's enabled subsystems easily handle such problems. We illustrate how to employ important Simulink modeling concepts in the creation of the clutch simulation. Designers can apply these concepts to many models with strong discontinuities and constraints that may change dynamically.

Open Model

Block Characteristics

Data Types

Boolean | double | fixed point | half | integer | single

Direct Feedthrough

yes

Multidimensional Signals

yes

Variable-Size Signals

yes

Zero-Crossing Detection

no

Extended Capabilities

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

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

Fixed-Point Conversion
Design and simulate fixed-point systems using Fixed-Point Designer™.

See Also

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Introduced before R2006a

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