The above process can be repeated for all elements within the HMI. The logical conditions can include logic that executes based on user-input events. The actions resulting from logic can include calls to external functions, allowing the developer to specify the behavior of the system based on its inputs. When the specification is complete, it can be reviewed and tested. At this point, the model represents the low-level requirements of the HMI, and it is ready to be moved to the next stages of the process including testing and deployment in an open-architecture HMI system.
The solution must allow for the equivalent of a compilation step while retaining the data-driven nature demanded by open architecture and certification. To realize the goals of our system, we designed a database format, called the HMI Specification Language (HSL). HSL is an efficient, compact, HMI representation format that captures geometry, logic, and user interactivity in a data-driven format. A graphical view of HSL is shown in Figure 3.
We implemented the run-time system, or HSL Rendering Library (HRL), to handle the task of rendering the HMI geometry and logic, maintaining the value of data inputs, and managing user interaction.
Subscribe today to receive the INSIDER, a FREE e-mail newsletter from Embedded Technology featuring exclusive previews of upcoming articles, late breaking NASA and industry news, hot products and design ideas, links to online resources, and much more.