Timer Off Delay Function Block

»Table of Contents

LabVIEW 2009 Real-Time Module Help

Edition Date: June 2009

Part Number: 370622G-01

»View Product Info

Owning Palette: Timer Function Blocks

Requires: RT Module

Generates an output signal with rising edges that align with the input signal, but with falling edges delayed by preset time (ms).

This function block generates an output signal that remains TRUE longer than the input signal by preset time (ms).

Details

Dialog Box Options

Block Diagram Inputs

Block Diagram Outputs

Dialog Box Options

Parameter	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.

Parameter

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.

Block Diagram Inputs

Parameter	Description
error in (no error)	Describes error conditions that occur before this node runs.
preset time	Specifies the amount of time for the function block to use in calculations.
input	Specifies the digital input signal.

Block Diagram Outputs

Parameter	Description
error out	Contains error information. This output provides standard error out functionality.
elapsed time (ms)	Returns the amount of time, in milliseconds, elapsed since the start of the delay. If no delay has started, this output returns the amount of time elapsed since the first call of the function block.
output	Returns the digital output signal.

Timer Off Delay Details

If a new rising edge occurs on input during the delay period, output remains TRUE and the delay period restarts at the next falling edge of input.

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.