The World Expo 2025 in Osaka, Japan, served as a global stage for technological innovation and cultural exchange, but few attractions captured the public’s imagination quite like the nightly multimedia water show, Under the Midnight Rainbow. Staged at the expansive Water Plaza, the production acted as the emotional crescendo for the Expo’s daily programming, drawing up to 2,500 spectators per performance. To achieve the level of precision required for such a massive undertaking—spanning 8,800 square meters and involving the synchronization of 300 water fountains, 30 flame effect stations, and a complex array of laser, video, and audio systems—the production firm ECA2 turned to the specialized expertise of db Show Control & Automation. At the core of this sophisticated technical ecosystem was the open automation technology provided by Beckhoff, which allowed for a seamless marriage between heavy industrial power and delicate artistic choreography.
Technical Scope and Artistic Vision
The Under the Midnight Rainbow show was not merely a fountain display; it was a highly engineered "theatre of elements." The installation featured a diverse array of water effects, including 280 straight water jets and eight high-dynamic 3D jets capable of complex kinematic movements. These were supplemented by two massive water screens and a specialized cascade screen designed to serve as a translucent canvas for high-definition video mapping. To add a visceral layer to the performance, 30 flame effect stations were integrated into the layout, along with high-pressure fog pumps that created a localized atmosphere regardless of the ambient weather conditions.
The artistic vision, led by ECA2, required these elements to move with deterministic accuracy. In a show where a flame burst must occur at the exact millisecond a water jet reaches its peak, traditional show control methods often struggle with latency. Aurelien Bouvier, Technical Director at ECA2, emphasized the importance of reliability in this high-stakes environment, noting that for an audience of 2,500 people to remain emotionally engaged, the underlying technology must remain invisible and infallible. Any "stutter" in the synchronization between the audio track and the visual effects would immediately break the immersion of the performance.
The Automation Architecture: A Foundation of EtherCAT
To manage the immense data throughput and the microsecond-level synchronization required, db Show Control & Automation designed a decentralized control topology. The "brain" of the operation was a Beckhoff CX5240 Embedded PC, located in a centralized main control room. This unit functioned as the primary show controller, overseeing the entire 8,800-square-meter site.
The field distribution was managed through eleven specialized control racks positioned strategically around the Water Plaza. These racks were interconnected using a high-speed EtherCAT backbone, supplemented by standard UDP/TCP Ethernet for non-critical data. One of the most impressive technical feats of the installation was the direct control of nearly 300 frequency converters via EtherCAT. This allowed the engineering team to achieve cycle times and levels of synchronicity that are typically reserved for high-speed industrial manufacturing lines.
Craig Pow Chong, Director of Engineering at db Show Control & Automation, highlighted that the choice of EtherCAT was instrumental in meeting the project’s requirements. By using a single, unified communication protocol, the team could control the physical movement of water and fire while simultaneously interacting with the AV systems via TCP/IP. This hybrid approach eliminated the need for complex "translator" hardware that often introduces lag and points of failure.
Environmental Monitoring and Functional Safety
Operating a large-scale multimedia show in the outdoor environment of Osaka Bay presented significant logistical and safety challenges. The region is known for variable wind patterns and high humidity, both of which can wreak havoc on fire effects and water projection screens. A key innovation in the Under the Midnight Rainbow project was the integration of a software-based environmental monitoring system directly within the Beckhoff TwinCAT control environment.
A network of sensors was deployed to monitor temperature, humidity, wind speed, wind direction, and water depth in real-time. This data was not merely logged for later review; it was used as an active input for the show’s logic. If the sensors detected a gust of wind exceeding a certain threshold in the direction of the spectator stands, the TwinCAT system would automatically adjust the frequency converters to reduce the height of the water jets or disable specific flame effects within milliseconds. This ensured that the audience remained dry and safe without requiring a manual "kill switch" that would have ended the show prematurely.
Functional safety was further bolstered by the use of TwinSAFE terminals (EL1918) and the Fail Safe over EtherCAT (FSoE) protocol. By integrating safety data into the existing EtherCAT network, the engineers avoided the need for extensive parallel wiring. This not only reduced the complexity of the installation but also provided a more granular level of diagnostic data, allowing the team to pinpoint potential issues before they resulted in a system shutdown.
Revolutionizing Show Playback with Ultra-Compact Hardware
Perhaps the most significant paradigm shift in the project’s technical execution was the move away from traditional, bulky server racks for show playback. For Under the Midnight Rainbow, db Show Control & Automation developed a proprietary recording and playback platform based on TwinCAT. This system ran on two Beckhoff C6017 ultra-compact Industrial PCs, configured in a master-backup redundancy setup.
Despite their small size—roughly the dimensions of a human palm—these PCs were capable of handling the playback of 32 DMX universes autonomously. This capability allowed for the complex lighting and effect cues to be executed with the same level of reliability as a high-end factory automation system. Craig Pow Chong noted that being able to record and play back a time-coded show sequence of this magnitude on such compact hardware represents a major shift in how the entertainment industry approaches infrastructure. The reduction in space, power consumption, and cooling requirements offered by the C6017 units provided significant cost and logistical advantages during the setup phase at the Expo.
Data Logging and Operational Reliability
The 184-day duration of World Expo 2025 required a system that could withstand constant use without degradation. To manage this, the production utilized the TwinCAT Database Server to log every piece of data generated by the sensors and the control system. This allowed for real-time monitoring and deep-dive diagnostics. If a pump showed signs of increased power consumption or if a valve’s response time began to drift, the maintenance team could address the issue during the day, ensuring that the nightly show remained unaffected.
The results of this rigorous engineering approach were evident in the show’s performance metrics. Over the six-month run of the Expo, approximately two million people viewed Under the Midnight Rainbow. According to the production team, the show did not suffer a single technical failure during this period. This level of "six-nines" reliability is rare in the world of large-scale outdoor entertainment and serves as a testament to the robustness of the Beckhoff-based architecture.
Industry Impact and the Future of Stage Automation
The success of the Osaka Expo show has broader implications for the global entertainment industry. For decades, the industry relied on proprietary, "black box" show controllers that were often difficult to integrate with standard industrial equipment. The Under the Midnight Rainbow project demonstrates a clear trend toward the "industrialization" of entertainment, where open standards and high-performance PLC (Programmable Logic Controller) technology are becoming the preferred choice for complex installations.
David Birchall, CEO of db Show Control & Automation, remarked that Beckhoff stands out as a manufacturer capable of bridging the gap between industrial-grade hardware and the specific protocols used in the arts, such as DMX, sACN, and QSC audio integration. This convergence allows designers to dream bigger, knowing that the underlying technology can handle the complexity of their visions.
As the entertainment world moves toward more interactive and data-driven experiences, the ability to integrate environmental sensors, safety protocols, and high-speed motion control into a single software platform will become the standard. The lessons learned at the Water Plaza in Osaka are already being applied to new projects, with db Show Control & Automation reportedly working on a follow-up installation of similar scale.
In conclusion, Under the Midnight Rainbow was more than just a highlight of World Expo 2025; it was a demonstration of how modern automation topology can transform a massive outdoor space into a precise, emotive, and safe theatrical environment. By leveraging the speed of EtherCAT, the flexibility of TwinCAT, and the reliability of industrial-grade hardware, ECA2 and db Show Control & Automation have set a new benchmark for the future of multimedia spectacles.
