# Set up connections for the Latched push button (Connections tab)

## To set up tags and expressions for the Latched push button

1. In the Graphics Display editor, double-click the button to open its Properties dialog box.
2. Click the Connections tab.
3. Assign a tag or expression to these connections:

   Value

   A read-write connection. Assign a tag to this connection. When the operator presses the button, the application writes the value corresponding to the latched state (State 1) to the tag’s data source, unless the Latch Reset Type option (on the General tab) is "Non-zero" and the Handshake connection is currently a non-zero value.

   When the Handshake connection unlatches the button, the application sends the value corresponding to the unlatched state (State 0) to the Value connection.

   When you open a display containing a Latched push button, the application reads the value of the Value connection to determine its current state.

   Indicator

   A read connection. You can assign a tag or an expression to this connection. The application reads the value of the connection at the data source, and updates the object’s display to reflect the state corresponding to the value.

   If you assign an expression, the application calculates the value of the expression and updates the object’s display to reflect the state corresponding to the value.

   If you assign this connection, the button does not show the current state until it receives a response from the Indicator connection. If you do not assign this connection, the button's state corresponds to the value at the Value connection.

   Handshake

   A read connection. You can assign a tag or an expression to this connection. The application reads the value of this connection at the data source, and resets the button to its unlatched state when this connection changes to meet the conditions of the Latch reset type option specified in the General tab.

   If you assign an expression, the application calculates the value of the expression and resets the button to its unlatched state when this connection changes to meet the conditions of the Latch reset type option.

   Tip: | To provide visual feedback that the Value connection has been written to the data source, assign different tags to the Value and Indicator connections. Configure the data source to pass the Value connection’s value to the Indicator connection.

## See also

Create Latched push buttons

Configure the Latched push button (General tab)

Set up states for the Latched push button (States tab)

How the Latched push button works at run time

Columns on the Connections tab of a graphic object's Properties dialog box