Systems Engineering Profinet Integration in Industrial Small Series

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BURGER Engineering & Co. KG

Hilscher Gesellschaft für Systemautomation mbH

Taiwan Machine Tool & Accessory Builders' Association (TMBA)

Wuxi InfiMotion Technology Co., Ltd.

The integration of a Profinet interface into an existing system is often complex – especially when time, development resources, and quantities are limited. This was precisely the challenge that had to be addressed during the network expansion of an industrial ultrasound solution.

A manufacturer of ultrasonic welding systems faced a specific challenge: the control of a new device version needed to be made Profinet-capable. In the previous model, control for adjusting frequencies, amplitudes, and other parameters was carried out via a serial interface based on an STM32 controller. For the new product generation, however, the end customer desired real-time communication via Profinet. The requirement was clear: the new interface had to seamlessly integrate into the existing system architecture, preferably without extensive hardware redevelopment or lengthy certification processes.

The project was managed on behalf of the end customer by the system developer Brückmann Elektronik and the systems engineering specialists at Burger Engineering. The choice of the appropriate communication module was crucial. Ultimately, the decision was made to use the Netrapid 90 from Hilscher, a provider of solutions in the field of industrial communication. Netrapid 90 is a fully tested, solderable communication module with an integrated netX 90 chip, which is delivered with the preloaded Profinet communication stack and can therefore be directly integrated into existing designs without complex hardware development.

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Alternatives were discussed, but due to the planned low production volumes, a separate PCB development (design-in of a netX 90) was quickly ruled out. The Netrapid 90 proved to be the most efficient solution with its compact design, complete communication and application unit, as well as the available development and certification tools. Due to a lack of experience with Profinet, especially in combination with the Hilscher hardware, Brückmann sought external support—and turned to Burger Engineering. The development team has been a certified official Hilscher "netX Design-In Partner" for several years and has extensive experience integrating Hilscher products.

Byte Mirroring Instead of Protocol Overhead

The core of the technical solution was the separation of application and communication logic. The existing STM32 controller, which already handled all device-specific functions such as frequency regulation, amplitude control, and power management, was not to be additionally burdened with Profinet communication. Initially, the plan was to operate the Netrapid 90 in the so-called Companion Mode—implementing the application in the STM32 while handling all communication to the Profinet network through the Netrapid 90. However, as the STM32 was already operating at its performance limits due to time-critical processes, the decision was made to implement the Netrapid in Stand-Alone Mode. This allowed application files to be exchanged between the provider and consumer via the second core of the netX 90 using the Profinet protocol. As a result, Profinet communication was achieved practically without any further performance loss for the STM32.

The connection to the STM32 was realized via an SPI interface. The Netrapid 90 acted as a master, directly retrieving process-relevant data from the STM32 control chip – or transmitting it to it. This cyclical process data exchange significantly increased the timing stability of the communication and also enabled later changes within the transmitted data.

The Profinet communication was configured so that the Netrapid 90 had no knowledge of the specific data contents. Instead, 64 bytes of provider data and 64 bytes of consumer data were exchanged cyclically as pure byte fields between the Profinet network and the STM32. In this way, it was solely the responsibility of the higher-level controller and the STM32 to interpret the contents of these data fields. For the application on the Netrapid module itself, this was irrelevant—it merely mirrored the data at defined intervals.

Shorter Development Time Than with an Integrated Chip Solution

This mirroring significantly reduced development effort: adjustments to the data structure—such as adding parameters, switching from 8-bit to 16-bit values, or introducing new control commands—could still be made towards the end of the project without needing to modify the communication layer again. It was precisely this decoupling that gave the project its high flexibility and speed. For the developer, this meant: no complex diagnostics, no extensive interpretation, no unnecessary parameterization—just a robust, flexible process data exchange. Additionally, development time was shortened with the Netrapid 90 from Hilscher as an embedded module solution, as the development effort was significantly lower compared to an integrated chip solution.

"With product development projects, we have long been offering an all-in-one package, which has recently been in higher demand from our customers. This is for various reasons, certainly including internal resource shortages. The days when product development could take many months are over. By using fully tested embedded modules with pre-installed firmware, we can drastically shorten the development cycle," explains Jörg Klenke, Project Management Officer (PMO) and member of the executive board at Burger Engineering.

In 9 Months and 2 Project Phases to the Final Product

The project was divided into two phases: an initial implementation phase and a second certification and optimization phase. The collaboration was structured as a division of labor between the system developer Brückmann, the communication expert Burger Engineering, and the hardware supplier Hilscher.

Phase 1: Implementation (February to June 2023): The project began with a joint workshop between Brückmann as the client and Burger Engineering as the development partner. During this workshop, the technical framework for the project was outlined, and a decision was made on whether a Companion Mode or a Standalone solution with SPI mirroring would be more suitable. Following an analysis of the controller load, the Standalone variant with SPI mirroring was chosen. The application was fully implemented on the Application Core of the Hilscher Netrapid 90. The development partner took on the complete implementation of the application and worked with evaluation boards during the early phase to test independently of the target hardware. In parallel, Hilscher delivered the Profinet protocol stack tailored to the Netrapid 90 hardware.

Phase 2: Optimization and Certification (June to September 2024): In the second phase of the project, the solution was prepared for Profinet certification based on preliminary tests. The development partner adjusted the data structure once again at the customer's request and expanded parameter ranges—the flexibility of the 64-byte mirroring proved invaluable here once more. The certification was conducted by the testing body Comded, located just a few kilometers from the development site. This enabled quick feedback loops: a necessary software update could be directly uploaded on-site without the need for a new registration.

Even in this phase, the efficiency of the communication module used became evident: selecting Conformance Class A and Netload Class 1 at the beginning of the project not only minimized development but also reduced certification efforts to the essentials. Features such as Profinet alarms, diagnostic functions, or complex parameterization were deliberately not implemented, as they were not required for the application and would have only added more time and costs.

Profinet Connection Implemented in Under Half a Year

At the end, a complete Profinet connection for an industrial power supply was realized in less than half a year and certified with minimal effort. Additionally, the solution can be easily adapted in the future or transferred to other device classes. Thus, a small-scale production project became an ideal entry point into Industrial IoT. The new ultrasonic welding device was successfully introduced at a relevant trade fair in 2025.

At Brückmann, they are very satisfied with the result, as Sebastian Wenzel, responsible for technical sales, explains: "The collaboration with Burger Engineering enabled us to realize a Profinet-capable solution for our customer in a very short time—despite the challenges of small-scale production development and subsequent changes. Particularly valuable for us was the combination of technical expertise and an extremely pragmatic approach. The result fully met our expectations, and we can well imagine relying on the team again for future projects."