Mr. Gräßer, Mr. Techert, what are the biggest challenges facing the design of an HMI today?
Philipp Gräßer: When it comes to technical development, software often lags behind the innovative possibilities offered by hardware. Modern systems contain more and more functions and provide more data. A good HMI must make this usable.
Thomas Techert: The customer experience is becoming increasingly important.

Young professionals today have grown up with smartphones, what does this mean for HMI in the industry?
Philipp Gräßer: First of all, it's a great opportunity that the next generation has such prior knowledge that HMI can build on.
Thomas Techert: On the other hand, industry is always different: the functions are more specialized and the tasks more complex than with home applications on iOS or Android. However, the absolute minimum requirement is that using the HMI is frustration-free; better still, that the expectations of use are met.
Philipp Gräßer: And the user must understand what is happening at all times. This also includes self-explanatory error messages, for example, so that they can initiate a solution on their own.

Can new technologies such as voice control or AR glasses also be used?
Philipp Gräßer: I haven't seen voice control in practice yet. It's also difficult in a noisy factory hall, for example.
Thomas Techert: AR and VR glasses are useful in some areas. For example, in machine maintenance. It just shouldn't be an end in itself.
Philipp Gräßer: I can also imagine visual control in the future. Experience has shown that most HMIs are simple touch displays. However, you shouldn't forget that the best user interface is the one you don't have because it's superfluous.

What role does HMI play in training?
Philipp Gräßer: It plays an important role in our development processes. In addition to intuitive operation, a good HMI also makes it easy to on-board new employees at the machine and even experienced workers can learn to work more efficiently with tool tips.

The wireframe can be used to test which displays are necessary and how they are sensibly arranged. © Gold trim

How does the development of a new HMI usually work in practice?
Philipp Gräßer: At the beginning, we define the goal of the project together with the customer: Which problem should be solved in which context? We then involve the users at an early stage: We systematically collect the requirements through surveys and observations. We use these to develop an initial structure and information architecture. We then develop an initial verifiable design.
Thomas Techert: This is a wireframe, i.e. the basic structure but still completely without design. We then evaluate this iteratively with the customer and, ideally, the users and improve it until all requirements are optimally met.

And the design?
Philipp Gräßer: Several factors play a role here: the environment in which the machine is to be installed is important for the brightness and contrast of the display. The corporate identity of the company and the design of the machine are also important factors.
Thomas Techert: It is best to develop a design system that contains all the building blocks for the entire design; a sustainable platform that can be used again and again and can be applied flexibly to changes and new products. As far as the process is concerned, ISO 9241-210 has been a standardized process for the HMI sector since 2010, which we use as a guide.
Philipp Gräßer: At the end of the process is the specification, which describes all the properties of the product, contains the components and is prepared for development.

The final phase is implementation. How does this work?
Philipp Gräßer: In most cases, implementation is carried out internally by the customer. We stay in direct contact with the development department and support them with our design expertise and user interface components.
Thomas Techert: For most customers, we do indeed supervise all steps from the initial concept to market maturity.

What trends do you see for the future?
Philipp Gräßer: Centralization. Systems will be networked, so control no longer has to take place at the machine. Thanks to automation, it will often be more about monitoring than controlling the systems.
Thomas Techert: Bring your own means that machines can be controlled as desired via the operator's individual end devices. One tablet is then sufficient for an entire system. Each operator also sees the control system in their own individual design, language or visual acuity.
Philipp Gräßer: Training will be able to take place on simulations.
Thomas Techert: There is also the question of whether visual interfaces will decline.