Logical Operator (Simulink Reference)

Perform the specified logical operation on the input

Library

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. The block updates to display the selected operator. The supported operations are given below.

Operation
Description

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

NOT
TRUE if the input is FALSE

Operation	Description
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
NOT	TRUE if the input is FALSE

The number of input ports is specified with the Number of input ports parameter. The output type is specified with the Output data type mode and/or the Output data type parameters. 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, etc.

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.

Data Type Support

The Logical Operator block accepts real or complex signals of any data type supported by Simulink, including fixed-point data types. However, if the Output data type mode parameter is set to Logical, the input may only be Boolean or double.

For a discussion on the data types supported by Simulink, refer to Data Types Supported by Simulink in the Using Simulink documentation.

Parameters and Dialog Box

The Main pane of the Logical Operator block dialog appears as follows:

Operator: The logical operator to be applied to the block inputs. Valid choices are the operators listed previously.
Number of input ports: The number of block inputs. The value must be appropriate for the selected operator.
Sample time (-1 for inherited): Specify the time interval between samples. To inherit the sample time, set this parameter to -1. See Specifying Sample Time in the online documentation for more information.

The Signal data types pane of the Logical Operator block dialog appears as follows:

Require all inputs and output to have same data type: Select to require all inputs and the output to have the same data type.
Output data type mode: Set the output data type to Boolean, or choose to specify the data type through the Output data type parameter.; Alternatively, you can select Logical to have the output data type determined by the Implement logic signals as boolean data parameter in the Simulation and code generation optimization pane of the Configuration Parameters dialog box. If you select Logical and Implement logic signals as boolean data is on, then the output data type is always Boolean. If you select Logical and Implement logic signals as boolean data is off, then the output data type will match the input data type, which may be Boolean or double.
Output data type: Output data type. You should only use data types that represent zero exactly. Data types that satisfy this condition include signed and unsigned integers and any floating-point data type. This parameter is only visible if you select Specify via dialog for the Output data type mode parameter.

Characteristics

Direct Feedthrough
Yes

Sample Time
Specified in the Sample time parameter

Scalar Expansion
Yes, of inputs

Dimensionalized
Yes

Zero Crossing
No

Direct Feedthrough	Yes
Sample Time	Specified in the Sample time parameter
Scalar Expansion	Yes, of inputs
Dimensionalized	Yes
Zero Crossing	No

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