# How the piloted control list selector works at run time

The piloted control list selector differs from the control list selector in that:

- it can be controlled remotely or by an operator (determined by the Remote Access property)
- it can be set to write out, not only the selected state, but also the state in the top position on the list, and/or all the states visible on the list, whenever the list scrolls (determined by the Top Position and Visible States connections)
- its Value connection is read to determine what state to select only when a display is opened
- it has an Indicator connection, which is used instead of the Value connection to select a state when the list is remotely controlled

Each state has an access property that determines whether that state can be selected remotely or by an operator, by both or by neither. When a new state is selected, if the state's Access property allows the selection, cursor moves to the state and the state is highlighted. If the object's Value connection is assigned, the state's value is written to the Value connection. If the Top Position connection is assigned, the value of the state at the top of the list is written to the assigned connection. If the Visible States connection is assigned, the values of all the state's visible in the list are written out.

## Open graphic displays

When you open a display at run time, the application reads the Remote Access connection value to see if the list is operator controlled or remotely controlled. If the Remote Access connection is unassigned, the list is operator-controlled.

If the list is operator controlled, the application reads the Value connection value and highlights the state with the matching value. The Value connection is not read at any other time. If no state matches the Value connection value, no state is highlighted and the cursor appears at the top of the list. If the operator selects a state whose Remote Access is set to Remote or to None, the cursor appears hollow.

If the list is remotely controlled, the application reads the value of the Indicator connection and highlights the state with the matching value. If no state matches the Indicator connection value, no state is highlighted and the cursor appears at the top of the list.

## Update the list once the display is open

The list is updated only when it scrolls, either through operator action or by remote control.

## If the list is operator controlled

- The operator can scroll through the list to select a different state, as long as the selected state's access property is set to Operator or to Operator and Remote (on the General tab).
- The operator can scroll and select states and write out the value associated with the selected state using key buttons, or by using the arrow keys and Enter key on a keypad or an external keyboard.
- If the selected state is not valid, that is, it is not selectable by the operator, or if the state's value is invalid, the highlight bar will not move. The cursor will move to the selected state, but it will be hollow, to indicate that the operator does not have access to the state.
- The list scrolls if it contains more states than can be viewed at one time. If "Wrap around" is selected in the General tab, when the operator reaches the bottom of the list and presses the Move Down button, the cursor moves to the top of the list. If the cursor is at the top of the list and the operator presses the Move Up button, the cursor moves to the bottom of the list.
- If "Write on enter" is selected (on the General tab), the value is not sent to the Value connection until the operator selects a valid state and presses the Enter button or Enter key. If "Write on enter" is not selected, the value is sent as soon as the operator scrolls to a new valid state.
- When the list scrolls, if the Visible States connection is assigned, the values for the states visible in the list will be written to the Visible States connection. If the Top Position connection is assigned, the value for the state in the top position on the list will be sent to the Top Position connection.

## Use auto repeat

If auto repeat is set up for the key button (on the key button's Timing tab) and the operator holds down the Move Up or Move Down button for the specified Auto repeat delay time, the list begins to scroll. If "Write on enter" is not selected, the application attempts to send a value to the Value connection for each state that scrolls by. However, some values may be lost if the Auto repeat rate is too fast for all the values to register.

## If the list is remotely controlled

- The application reads the value of the Indicator connection to determine what state to display. If the value of the Indicator connection matches a valid state, that is, one whose Access is set to either Remote or Operator and Remote, the state is highlighted and the value associated with the selected state is written to the Value connection, if it is assigned.
- When the list scrolls, if the Visible States connection is assigned, the values for the states visible in the list will be written to the Visible States connection. If the Top Position connection is assigned, the value for the state in the top position on the list will be sent to the Top Position connection.
- When the list is remotely controlled, the "Write on enter" selection does not apply.
- The cursor is not shown.

## See also

Create piloted control list selectors

Set up general properties for a piloted control list selector

Set up states for the piloted control list selector

Set up handshaking for the piloted control list selector

Set up connections for the piloted control list selector