LabVIEW learning note 5: you cannot return to the original state after pressing the button

The picture is like this

 

The button is this attribute

 

  Click execute , The serial port successfully issued this series of instructions , But this button is always pressed , Unable to return to the original state .

 

Later, I found that I didn't put the button control in while In circulation , After putting it in, it can be restored

The point is labview Whether to read the control value  

Control ？

Control (control)	Interactively to VI Input data or programmatically transfer to sub VI Front panel object for input data , Like a knob 、 Button or turntable .
Control palette (Controls palette)	Contains input controls in the front panel 、 Palette for displaying controls and decorative objects .

Use Control palette The input control and display control of are created for LabVIEW VI Front panel . Input controls and display controls provide a way to send input data to the program block diagram and receive output data . single click see » Control palette Or right click the front panel workspace , Show Control palette .

Mechanical action of Boolean control ？

The mechanical actions of Boolean controls are used to create real instruments （ Such as oscilloscope and multimeter ） Similar front panel behavior . The same thing about switching and triggering actions is that they both change the value of Boolean controls , The difference lies in how they restore the original value of the control .

• Switch action — If you want the control value to be restored to the previous value only by the user , Use this action .
• Trigger action — If you want to read the control's VI When restoring the control value to the previous value , Use this action . At this time, the user can also restore the control value to the previous value , But it must be in VI Before reading the control .

notes : Trigger action is incompatible with local variables , And when trigger action is used in the event structure , Usually place the Boolean control terminal at “ Value change ” Within the event structure .