Simulink Reference

Detect Fall Nonpositive

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

Library

Logic and Bit Operations

Description

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

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

Data Type Support

The Detect Fall Nonpositive 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 Negative, Detect Increase, Detect Rise Nonnegative, Detect Rise Positive

Detect Fall Negative

Detect Increase

© 1994-2005 The MathWorks, Inc.