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Logical Operator

Perform specified logical operation on input

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  • Logical Operator block

Libraries:
Simulink / Commonly Used Blocks
Simulink / Logic and Bit Operations
HDL Coder / Commonly Used Blocks
HDL Coder / Logic and Bit Operations

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.

Examples

Model Fault-Tolerant Fuel Control System

Model Fault-Tolerant Fuel Control System

Combine Stateflow® and Simulink® capabilities to 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 in this example represents a fuel control system for a gasoline engine. The system is robust in that it detects individual sensor failures, and the control system is dynamically reconfigured for uninterrupted operation.

Model Stick-Slip Friction and Hard Stops in Mass-Spring-Damper System

Model Stick-Slip Friction and Hard Stops in Mass-Spring-Damper System

One way you can incorporate hard stops and friction changes from stick-slip motion into a mass-spring-damper 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 enabled subsystem can 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.

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 — 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

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 time interval between samples. To inherit the sample time, set this parameter to -1. For more information, see Specify Sample Time.

Dependencies

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

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

Parameter: SampleTime
Values: "-1" (default) | scalar or vector in quotes

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

    The Data Type Assistant helps you set data attributes. To use the Data Type Assistant, click the Show data type assistant button. 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'

Select the category of data to specify.

  • Built in — Specifies built-in data types. Selecting Built in enables boolean.

  • Inherit — Specifies inheritance rules for data types. Selecting Inherit enables Logical (see Configuration Parameters: Optimization).

  • Fixed point — Specifies fixed-point data types.

  • Expression — Specifies expressions that evaluate to data types.

Dependencies

To enable this parameter, click the Show data type assistant button.

Select the data type override mode for this signal.

  • When you select Inherit, Simulink inherits the data type override setting from its context, that is, from the block, Simulink.Signal object or Stateflow® chart in Simulink that is using the signal.

  • When you select Off, Simulink ignores the data type override setting of its context and uses the fixed-point data type specified for the signal.

For more information, see Specify Data Types Using Data Type Assistant in the Simulink documentation.

Dependencies

To enable this parameter, set Mode to Built in or Fixed point.

Tips

The ability to turn off data type override for an individual data type provides greater control over the data types in your model when you apply data type override. For example, you can use this option to ensure that data types meet the requirements of downstream blocks regardless of the data type override setting.

Specify whether you want the fixed-point data as signed or unsigned. Signed data can represent positive and negative values, but unsigned data represents positive values only. For more information, see Specifying a Fixed-Point Data Type.

Dependencies

To enable this parameter, set Mode to Fixed point.

Specify the bit size of the word that holds the quantized integer. For more information, see Specifying a Fixed-Point Data Type.

Dependencies

To enable this parameter, set Mode to Fixed point.

Specify the method for scaling your fixed-point data to avoid overflow conditions and minimize quantization errors. Specifying Integer has the same result as specifying a binary point location and setting the fraction length to 0.

Dependencies

To enable this parameter, click the Show data type assistant button and set Mode to Fixed point.

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™.

Version History

Introduced before R2006a

See Also

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