Revolutionising Industrial Control Via Innovative User Interface Approach

Author : Dr Andrew Morrison, Technical Director at Zytronic

20 October 2023

Figure 1: All-in-one hybrid control panel with touch display, keyboard and fixed buttons located outside of the main display touch area
Figure 1: All-in-one hybrid control panel with touch display, keyboard and fixed buttons located outside of the main display touch area

When designing a control panel for a piece of industrial equipment, the first thing to do is identify the specific needs and preferences of the users. Taking the food processing industry as an example, careful consideration must be given to ensure hygiene and safety, as well as compliance with regulations. The ability to develop tailored user interface hardware that prioritises food safety and operational efficiency is paramount.

To ensure that the items produced on their premises are safe to eat, food businesses must implement and maintain a safety management system based on hazard analysis critical control points (HACCP) principles. The focus of this system is on preventing issues, such as foreign body particle contamination before they develop, and it is regarded as the most successful method of regulating food-borne diseases by international authorities.

Mechanical to electronic interfaces
Traditionally, mechanical buttons and switches have been used for machine system control as they are known for their robustness and durability. They are generally simple and intuitive to use - even when the operator is wearing protective gloves, which is another critical consideration in food processing industries. Mechanical controls can also withstand regular exposure to harsh chemical washdowns without external degradation or compromises in performance. However, they typically have physical gaps and crevices that can trap contaminants and bacteria, making them challenging to clean thoroughly. 

With the age of digitalisation and the Industrial Internet of Things (IIoT), control panels outside the food sector have evolved - shifting from mechanical to digital format. Electronic interfaces, like touchscreens, offer distinct advantages. They can adapt to different tasks and display real-time data, graphs and trends, providing operators with valuable information at their fingertips. Easy software updates offer opportunities for ongoing improvement and feature enhancements - and even accommodate the multilingual requirements of the end user. 

For the food sector, touchscreens are the obvious choice too. Operators can quickly and safely control the equipment without worrying about contamination or accidental activation. The touchscreens are also designed to be easy to clean and maintain, even with disinfectant chemicals, further enhancing the hygiene of the equipment.

Zytronic’s patented PCAP touch technology will detect direct finger contact much like a smartphone’s touchscreen, but through much thicker and more robust glass thicknesses of 10mm or greater if needed in the final application. It also supports gesture controls, such as swipes and pinches but, more importantly, it still works when the user wears gloves. Furthermore, clever 'palm rejection' programming embedded into the controller's firmware avoids potential false touches from foreign bodies, which may reside on the surface of the sensor or if the user accidentally leans on the sensing surface. 

Addressing specific needs
Within the food sector, even the slightest possibility of glass contamination or substrate fallout in the event of screen damage is unacceptable, making their use risky. In understanding of this requirement, Zytronic has developed a proprietary film overlay, laminated to the surface of its proprietary PCAP touchscreen solution to mitigate this risk. Even in the rare and unfortunate circumstances when the touch sensor glass substrate becomes broken, no contamination can spall from the surface whilst the touch functionality remains fully operational, thereby ensuring that safety and hygiene can be maintained until a replacement is installed. 

Figure 2: Contactless sensing offers distinct plus points in situations where physical touch must be avoided
Figure 2: Contactless sensing offers distinct plus points in situations where physical touch must be avoided

Touch innovations
Zytronic has developed special controller firmware so that dynamic touch sensing areas can be defined. This capability creates a hybrid of touch functionality alongside the traditional display area, such as providing fixed touch button positions outside of the main display (see Figure 1). Working closely with customers, the touch interface is designed, glass is cut, printed and toughened in-house. Customisation of the firmware can be carried out on request, defining the button functions and desired output protocol for the final application.

Operation of the on-glass keyboard function is achieved before loading of the native Windows desktop, as it boots as a native human interface device (HID) keyboard. This allows keyboard functionality via the sensor even at the boot level. Hybrid PCAP touch sensors can be manufactured in almost any size and specification. Customers can also specify other customisations - such as special edge profiling and glass curvature. Cut-outs and holes may be added to incorporate such devices as card readers and emergency stop buttons. Once the glass has been machined, customer branding can be reinforced by adding graphics and logos that can be produced in a wide variety of colours. Ceramic inks, which are highly scratch-resistant, are recommended for rugged applications. To provide full integrity and longevity of the product, the inks are fired into the rear of the touchable glass during the glass toughening process. 

The addition of a Z-axis dimension to the PCAP touch technology has allowed contactless sensing to be benefitted from (see Figure 2). With complete control over the sensitivity levels via the controller’s firmware algorithms, it is possible to dynamically switch between sensitivity measurement levels of the sensor and detect user interactions up to 30mm away from the surface of the glass, even when the user is wearing thick gloves. The increased Z-axis sensitivity can also be turned on and off via external API commands sent from the host. This enables the control panel to dynamically switch between contactless and direct touch optional modes, depending on the intended application and usage needs.

Innovation through conversation
User interface hardware design teams and machine builders need continuous support throughout their development processes - as they consider the breadth of functionality, the environments in which their control panels will be used, and any safety or regulatory requirements that must be met. Having an open dialogue between touch solution producers and their customers is pivotal - meaning that critical design criteria are understood, as well as sparking new touch innovations that will be advantageous in the future. 

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