Using both soft and hard tactics: The development of "Bai Fu Mei" HMI products

There are more and more machines working for humans, and they are doing more and more work for humans. This requires an effective way of communication between humans and machines to "express feelings and ideas" for both parties, so human-machine interface (HMI) products are born. From the earliest physical interaction interfaces such as switches, to graphical interaction interfaces, and then to the natural interaction interfaces such as gestures and voice that are now at the forefront, HMI has been constantly evolving.

However, the mainstream HMI products in the market are still graphical HMIs, and this market has been growing steadily. It is expected that the global HMI market will reach US$4.05 billion by 2017. Although the growth rate of the industrial market, which is the origin of HMI products and the largest payer, has slowed down in the past two years, there are two important factors that make people still optimistic about its future: first, the global smart manufacturing boom is expected to become a new driving force for the industrial HMI market; at the same time, with the development of the Internet of Things, emerging markets have begun to exert their strength, such as retail, finance, medical care, entertainment, transportation and other markets, and the application of graphical HMI will become more and more common.

The core function of an HMI system is to connect with the monitoring or data acquisition system to complete functions such as system status diagnosis, trend prediction, information management, and present important information to users, so that users can understand the system operation status in a timely manner and make judgments and controls. The hardware of HMI products usually includes several main parts such as processor, display, data storage and interface, which work together with related software to complete its functional roles. In the industrial field, the introduction of HMI products is mainly due to efficiency and safety considerations. Operators at industrial sites can make intuitive judgments and feedback through a graphical human-machine interface. Early warnings based on data analysis and system abnormality alarms enable people to take quick action. In other application scenarios, HMI will also play a similar role, making communication between users and machines more convenient, natural and efficient.

So what should a "good" HMI product look like? First, it should have sufficient hardware performance to drive it to complete data processing and display, as well as rich data input and output functions; second, it should be scalable to adapt to the needs of diverse and changing application scenarios; third, it should have a flexible and easy-to-use software platform to facilitate graphical interface design; fourth, a friendly interface design to enhance user experience. Among these four elements, the first two are hard skills, and the last two are soft skills.

In terms of hardware, the choice of processor plays a decisive role. Currently, HMI product developers have many choices in the two processor architectures of x86 and ARM. With the intensification of competition, the requirements for HMI processors are becoming more and more detailed. Some people have summarized three aspects: the first is high performance, low power consumption and small size; the second is security and encryption; and the last is cheap. Therefore, processor manufacturers have to cater to the market and develop "matching" products. For example, the i.MX 6UL launched by NXP in the past two years uses the ARM Cortex-A7 processor core with a main frequency of 528MHz. While ensuring high performance, the power consumption is 50% lower than that of the Cortex-A9 core. At the same time, the pixel pipeline can provide 2D graphics acceleration function, support encryption engine and secure boot, and is equipped with rich memory and peripheral interfaces. It can be regarded as tailor-made for HMI products.

In terms of application scalability, the HMI-specific development platform launched by Avnet based on i.MX 6UL is worth learning from. The solution includes an i.MX 6UL SOM (system-level module) and an application baseboard. The SOM is a core board that contains the necessary hardware resources for the processor core. It is connected to the application baseboard through a SODIMM interface. For different target applications, the development and evaluation platform can be formed by replacing the application baseboard. Avnet's dedicated baseboard optimized for HMI product design covers the core functions required by HMI products, making it convenient for developers using i.MX6UL SOM to focus on product development and shorten the R&D cycle.

In terms of software, configuration software developed from industrial control applications can support developers to quickly design graphical interfaces. Currently, developers can find mature configuration software products on the market, and many products are cross-platform and support multiple operating systems, including mobile OS, which greatly expands the application scope and product form of HMI. However, configuration software only provides a tool. To truly design a user interface for an HMI product, developers also need to have knowledge and skills in user experience design and a deep understanding of design rules.

The user interface of an excellent HMI product should first be able to enhance the user's ability to perceive the system status, discover important data, and present it intuitively; secondly, it should effectively reduce the user's cognitive load, assist the user or even make judgments on behalf of the user; thirdly, the user interface should have clear and logical information classification and navigation, so that users can "act" quickly and accurately. Of course, in addition to the above general principles, developers are also required to have a more professional understanding of HMI application scenarios, such as an understanding of the "connotation" of industrial data.

In short, developing an HMI product that users will like is like raising a beautiful, wealthy daughter. If you want her to marry well, developers really need to be more thoughtful.