Constant Button
Overview
Use this operator if a constant value should be set anywhere in a measurement configuration, that can be changed by the end-user by pressing a button.Operator ports
Output K1 | K2: Floating point valuesThis is a Constant output, which does not output a signal, but a single value. A constant output does not have a sample frequency and is therefore recognized by Polybench to be a constant. Many calculations can be performed on constants as well as signals (or a combination of both). If an operator performs a calculation on constants only, it becomes a constant operator itself.
Constants and any other data source are allowed to be mixed without synchronization ("Synchronizer").
In a schematic, connectors that are connected to constant outputs are always colored black, while connections from other data sources may be colored differently.
Paired User Interface Object
This operator is loaded simultaneously with a user interface object. The user interface object can be moved to another page, and would normally be displayed in the end-user application. The operator and this user interface object can never be separated. If you delete the operator, the user interface is deleted automatically as well. Note that you cannot delete the user interface, only the operator symbol!Properties
Find more information about changing properties here: "Properties Viewer"Unit
type: See descriptionThe unit of the constant value. This value is optional and per default empty.
ValuePress
type: See descriptionThe constant value at the output channel when the button is pressed.
ValueRelease
type: See descriptionThe constant value at the output channel when the button is NOT pressed.
ButtonText
type: See descriptionThe text on the button.
ToggleText
type: See descriptionThe text on the button if it is toggled. Only works if ButtonType is 'Toggle'.
ButtonType
type: Select from the listSelect the button type: trigger (default) or toggle.
Select one of those presets:
Trigger
Trigger type botton (one shot)
Toggle
Toggle type button (state)
Trigger
Trigger type botton (one shot)
Toggle
Toggle type button (state)
ButtonFormat
type: Known button type nameThe name of the button format in the Button Repository, used to draw this button.
This property selects a button layout from the Button Repository. For more information about the use of buttons in a project, refer to "Button Repository"
Caption
type: Word or phraseThe name of the object in the project. This name must not contain '.', '$' nor '@' characters.
For more information about the rules and usage of the Caption property, please refer to "Caption property - background and usage".
Documentation
type: See descriptionOptional documentation of this object. If this object is an operator, the Documentation text is displayed below the operator symbol.
Variable Parameters
Find more information about Variable Parameters here: "Variable Parameters"ButtonState
type: See descriptionButton state, which is either Pressed (1) or Released (0). If you put a non-zero value in this variable, then this has the result as if the button is pressed or set to be toggled.
Functions
Find more information about Functions here: "Operator Functions"Enable
Sets the button to Enabled, so that it accepts user input.Disable
Sets the button to Disabled, so that it does not accept any user input.
Details
The Constant Button does not immediately change its output when the button is pressed, if the project has not been started. The reason for that, is that the Constant Button tries to synchronize the output change with other running signals. As a result, the output change after pressing the button may be delayed anywhere between 0 and approx. 15 ms. Also, the Constant Button only changes its state if processing has been started (so: after a START action).It is possible to change or read the button state from inside the project, by writing or reading a 0 or 1 to or from the ButtonState variable parameter.
In Trigger mode, writing 1 to ButtonState has the same effect as pressing the button, and writing 0 has the effect of releasing the button. Note that if you forget to write a 0 after writing a 1, this is like pressing the button continuously.
In Toggle mode, this parameter may be 1 for as long as the button is toggled. If you write 1 to ButtonState, then the button is set toggled (this is the same as pressing and immediately releasing the button). If you write a 0, then the button is set to the Released state (this is the same as again pressing and immediately releasing the button).