Simulink Reference

Logical Operator

Perform the specified logical operation on the input

Library

Simulink Math Operations and Fixed-Point Blockset Logic & Comparison

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 icon 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

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.

When the Show additional parameters check box is selected, some of the parameters that become visible are common to many blocks. For a detailed description of these parameters, refer to Block Parameters in the Fixed-Point Blockset documentation.

Data Type Support

A Logical Operator block accepts real or complex signals of any data type except int64 and uint64. However, if the Output data type mode parameter is set to Logical, the input may only be boolean or double.

Parameters and Dialog Box

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.

Show additional parameters

If selected, additional parameters specific to implementation of the block become visible as shown.

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 Boolean Logic Signals parameter in the Advanced tab of the Simulation Parameters Interface. If you select Logical and Boolean Logic Signals is on, then the output data type is always Boolean. If you select Logical and Boolean Logic Signals 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 Specify via dialog is selected for the Output data type mode parameter.

Characteristics

Dimensionalized	Yes
Direct Feedthrough	Yes
Sample Time	Inherited from the driving block
Scalar Expansion	Of inputs
Zero Crossing	No

Interpolation (n-D) Using PreLook-Up

Look-Up Table