Detects a falling edge, a transition from TRUE to FALSE, on the input signal. When a falling edge occurs, output is TRUE for one function block execution. The value of output remains FALSE until a new falling edge occurs.


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Dialog Box Options

Option Description
Inputs Contains the following configuration options:
  • Terminal name—Contains the name of the block diagram terminal to configure.
  • Visible?—Specifies whether to display the terminal on the block diagram.
  • Variable scope—Specifies the availability and scope of the variable associated with the terminal. Select Single-process to use a single-process shared variable. Select Network-published to use a network-published shared variable. Select No Variable if you do not want to use a terminal variable. To minimize overhead, include function block terminal variables only when necessary. If you change the Variable scope to No Variable after creating the function block instance, LabVIEW deletes the terminal variable.
  • Data source—Specifies the data source of the input. Select Terminal to wire the input value to the terminal on the block diagram. Select Variable to supply the input value to the function block through the associated terminal variable, if available. Select Default value to use the Default value. The Variable data source option is not available if you select No Variable under Variable Scope. If you select Terminal as the data source and leave the block diagram terminal unwired, LabVIEW uses the Default value.
  • Default value—Specifies the default value of the input. If you select Variable as the data source, LabVIEW uses this value as the initial value of the variable. If you select Default value as the data source, LabVIEW uses this value for every iteration of the function block.
Outputs Contains the following configuration options:
  • Terminal name—Contains the name of the block diagram terminal to configure.
  • Visible?—Specifies whether to display the terminal on the block diagram.
  • Variable scope—Specifies the availability and scope of the variable associated with the terminal. Select Single-process to use a single-process shared variable. Select Network-published to use a network-published shared variable. Select No Variable if you do not want to use a terminal variable. To minimize overhead, include function block terminal variables only when necessary. If you change the Variable scope to No Variable after creating the function block instance, LabVIEW deletes the terminal variable.

Inputs/Outputs

  • cerrcodeclst.png error in —

    error in describes error conditions that occur before this node runs. This input provides standard error in functionality.

  • cbool.png input —

    Specifies the digital input signal.

  • ierrcodeclst.png error out —

    error out contains error information. This output provides standard error out functionality.

  • ibool.png output —

    Returns the digital output signal.

    • The timing of this function block depends on the rate of the Timed Loop or While Loop in which you place the function block. For example, if you need the function block to update with millisecond resolution, you can place the function block in a Timed Loop configured to execute every millisecond.

    The following timing diagram illustrates the behavior of this function block.