A user looking at the field for providing a control input should be able to determine which plant component or variable is being controlled.
Additional Information:
The design of a soft control should provide a salient link between the input field and the corresponding variable or component. Starting at the input field, the operator should be able to quickly trace the component or variable back to its representation in the display that was used to select it. Three methods that might be used are graphic coding, landmarks, and animation. Graphic codes, such as borders, symbols, and colors, may be applied to both the representation of the component in the display from which it was selected and to the input field, making a strong visual association between them. For example, if the selection display has a mimic format, the input field may contain the symbol for the selected component. It also may contain symbols for the components that precede and follow it in the flow path. Animation may be used when an input field is opened and closed. The input field could appear as if it were 'popping out' of an option selected from a display, and 'go back' into the option when the field is closed.