How a latched push button works at runtime

If the Latch reset type (specified in the

General

tab of the Latched Push Button Properties dialog box) is Non-zero, when the Handshake connection is a non-zero value, the application unlatches the button. If the operator presses the button while the Handshake connection is a non-zero value, the button remains unlatched.

If the latch reset type is

Zero to non-zero transition

, when the Handshake connection changes from 0 to a non-zero value, the application unlatches the button.

If the button is in the latched state and the operator presses the button, the application writes out the latched (State 1) value again.

If you assign just the Value connection and not the Indicator connection, the button’s pressed state is displayed as soon as the button is pressed. The feedback for this connection is local and immediate. It does not necessarily reflect the value of the Value connection in the data source.

If you assign the same tag to the Value and Indicator connections, at runtime the displayed 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.

When you open a display at runtime, the application reads the Indicator connection and sets the button to that state.

If the value does not match either state’s value, the error state is displayed. When the operator presses the button, it changes to State 1.

When you open a display at runtime, the application reads the value of the Indicator connection and updates the display based on the value.

When you open a display at runtime, the application reads the value of the Handshake connection.

When you close a display at runtime, subsequent changes to the Handshake connection do not affect the latched push button.