Simulink Reference

Detect Fall Negative

Detect a falling edge when the signal's value decreases to a strictly negative value, and its previous value was nonnegative

Library

Logic and Bit Operations

Description

The Detect Fall Negative block determines if the input is less than zero, and its previous value was greater than or equal to zero where

• The output is true (not 0), when the input signal is less than zero, and its previous value was greater than or equal to zero.
• The output is false (equal to 0), when the input signal is greater than or equal to zero, or if the input signal is nonnegative, its previous value was positive or zero.

Data Type Support

The Detect Fall Negative block accepts signals of any data type supported by Simulink, including fixed-point data types.

Parameters and Dialog Box

Initial condition

Set the initial condition of the Boolean expression U/z < 0.

Characteristics

Direct Feedthrough	Yes
Scalar Expansion	Yes

See Also

Detect Change, Detect Decrease, Detect Fall Nonpositive, Detect Increase, Detect Rise Nonnegative, Detect Rise Positive

Detect Decrease

Detect Fall Nonpositive

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