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Owning Palette: Timer

Installed With: RT Module

Counts down from the number you specify using the preset value input. The counter value output decrements on each rising edge of the count down input. When counter value reaches zero, done returns TRUE.

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 select a variable scope of No Variable for an input or output when you create a new function block instance, LabVIEW does not create a terminal variable for that input or output. If you change the value 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 as a constant 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 as a constant 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 as a constant value.
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 select a variable scope of No Variable for an input or output when you create a new function block instance, LabVIEW does not create a terminal variable for that input or output. If you change the value 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 function block runs. If an error occurs, the function block does not execute.
preset value	Specifies the number to count up to or down from.
load	Sets counter value to preset value.
count down	Specifies whether to decrement counter value. Each rising edge of this input triggers counter value to decrease by one.

Block Diagram Outputs

Parameter	Description
error out	Contains error information. If error in (no error) indicates that an error occurred before this function block ran, error out contains the same error information. Otherwise, it describes the error status that this function block produces. Right click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error.
counter value	Returns the current value of the counter.
done	Indicates when the function block finishes counting down.

Count Down Details

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.