Relay Function
Owning Palette: Nonlinear Systems Functions
Installed With: Control Design and Simulation Module
Returns one of two values based on the value of the input signal.
| Dialog Box Options |
| Block Diagram Inputs |
| Block Diagram Outputs |
 Place on the block diagram |
Find on the Functions palette |
Dialog Box Options
| Parameter | Description |
|---|---|
| Polymorphic instance | Specifies whether this function is Scalar or Vector. The default value is Scalar. |
| Parameters | Lists all the parameters associated with this function. Select a parameter from this list to configure the parameter. When you select a parameter, the parameter and its associated Parameter source control appear in the Parameter Information section of the configuration dialog box. |
| Preview | Displays a graphical preview, if available, of the function output or configuration. |
| Parameter Information | Contains the parameters you can configure for this function. You must select a parameter from the Parameters list to make that parameter and its associated Parameter source control visible in the Parameter Information section of the configuration dialog box. |
| Parameter source | Specifies whether you configure this parameter using the Configuration Dialog Box or a Terminal on the simulation diagram. The default value is Configuration Dialog Box. If you select Terminal, LabVIEW displays an input for that parameter on the simulation diagram, and you can wire values to that input to configure this function programmatically. If you select Configuration Dialog Box, LabVIEW removes that input from the simulation diagram. You then must set the value for this parameter inside the configuration dialog box. |
| output when off | Specifies the value of the output when the relay is in the off state. The default value is –10. |
| output when on | Specifies the value of the output when the relay is in the on state. The default value is 10. |
| switch off point | Specifies the value below which the input must fall to switch from the on state to the off state. The default value is –1. The value of this parameter must be less than or equal to the value of the switch on point parameter, or LabVIEW returns an error. |
| switch on point | Specifies the value above which the input must rise to switch from the off state to the on state. The default value is 1. The value of this parameter must be greater than or equal to the value of the switch off point parameter, or LabVIEW returns an error. |
Block Diagram Inputs
| Parameter | Description |
|---|---|
| output when off | Specifies the value of the output when the relay is in the off state. The default value is –10. |
| output when on | Specifies the value of the output when the relay is in the on state. The default value is 10. |
| switch off point | Specifies the value below which the input must fall to switch from the on state to the off state. The default value is –1. The value of this parameter must be less than or equal to the value of the switch on point parameter, or LabVIEW returns an error. |
| switch on point | Specifies the value above which the input must rise to switch from the off state to the on state. The default value is 1. The value of this parameter must be greater than or equal to the value of the switch off point parameter, or LabVIEW returns an error. |
| input | Specifies the signal to which you want to apply the function. |
Block Diagram Outputs
| Parameter | Description |
|---|---|
| output | Returns the signal that results from applying the function to the input signal. |
Relay Details
The following equations define the output of this function.
When the relay is in the on state, the relay remains in the on state until the input falls below the value of the switch off point. When the relay is in the off state, the relay remains in the off state until the input exceeds the value of the switch on point. The relay initially is in the off state.
Feedthrough Behavior
All input/output pairs of this function have direct feedthrough behavior.
Example
Refer to the SimEx relay VI in the labview\examples\Control and Simulation\Simulation\Nonlinear directory for an example of using the Relay VI.
Open example Browse related examples