The enormous variability and operational complexity and cognitive of automation programming represents an expanded challenge for performance-centered design and performance-support concepts, requiring techniques that go beyond many of the more traditional and established approaches to user interface design.
The Step 7 Lite design of user interface is based on a new paradigm for complex user interfaces that can be described as instructive interaction. The Users learn how to use a system through the process of using it, rather than through separate instruction, manuals, or tutorials with instructive interaction. The objective of instructive interaction is to make complex systems self-teaching.
Interaction of instructive integrates a diverse body of established and innovative techniques to render novel user interfaces immediately understandable and usable. Feedback and guidance are intrinsic to the user interface itself and are provided in context with instructive interaction. Thus, for instance, PLC programmers using Step 7 Lite are not told in advanced precisely how to set up a configuration of hardware modules, they are not stepped through a fixed or inflexible sequence and they are not informed after the fact by error messages should they attempt an incorrect or illogical arrangement. Instead, the moment they attempt to add a module of hardware to a configuration, the appearance of the system changes to convey where that module may or may not be placed. Likewise, they do not need to be told that the tabular and graphic views are synchronized and connected in a certain way; any attempt to operate on either immediately reveals the relationship and is reinforced with visual cues that show exactly which element in one view corresponds to which in the other. The novelty and success of this approach rests not so much in any one technique but in the way in which all the details fit together and reflect an underlying insight into the detailed nature of the supported tasks.