How the Maintained push button works at runtime

This button works like a hard-wired switch. When the operator first presses the button, it changes from State 0 to State 1 and sends the State 1 value to the data source. When the operator presses and
releases
 the button a second time, it changes from State 1 back to State 0 and sends the State 0 value to the data source.
The
Maintained
 push button’s behavior at runtime also depends on how you set up the
Next state based on
 option and controls.
Change states
  • The application uses the
    Next state based on
     option (specified on the
    General
    tab of the
    Maintained Push Button
     dialog box) to determine how to change the button’s state.
  • If
    Next state based on
     is set to Value connection, and the control’s value does not match either state’s value, the button is set to State 0 and the application writes the State 0 value to the data source.
Use controls
  • If you assign just the Value connection and not the Indicator connection, the button’s state is shown as soon as the button is pressed. The feedback for this connection is local and immediate. It does not necessarily reflect the Value connection’s value in the data source.
  • If you assign the same tag to the Value and Indicator controls, at runtime the shown button state is based on the Indicator connection. If network traffic is heavy, the display response might be delayed.
  • If the Indicator connection value is a floating point value, the application rounds the value to the nearest integer to determine the state to display.
Start projects
When your display is opened at runtime, the application reads the Value connection and sets the button to the state for that value, regardless of the
Next state based on
 setting.
Open graphic displays
  • When you open a display at runtime, the application reads the button’s Value connection and sets the button to the state for that value. If the Indicator connection is not assigned, the shown state is based on this value.
  • When you open a display at runtime, the application reads the Indicator connection value and updates the display based on the value.
    If the value does not match either state’s value, the error state is shown. When the operator presses the button, it changes to State 0.
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