Demag Cranes & Components is part of Konecranes, a global leader in industrial bridge cranes, crane components, and material handling services. To enhance crane efficiency, safety, and ergonomics, Demag is advancing the development and research of innovative crane assistance features, such as automated operator following and tandem operation for moving large loads. The goal is to offer these new functions as retrofit options for existing systems, without the need for costly new data cable installations. To ensure precise, highly synchronous maneuvers, there is no room for error in communication between cranes in terms of reliability and latency: in Smart Tandem mode, the delay in exchanging CAN bus control data must not exceed the critical threshold of 20 ms. If exceeded, the cranes are stopped for safety and put into a safe state.
Most wireless technologies cannot meet these requirements or fail to do so reliably over a prolonged period. Conventional Wi-Fi could not support uninterrupted operation. Even a private 5G network did not achieve the necessary quality of service. Both technologies repeatedly experienced latencies that significantly exceeded the required 20 ms. To operate over Wi-Fi or 5G, the cranes would need to move more slowly to tolerate larger latencies while maintaining precision, hence reducing productivity. Other specialized technologies allow point-to-point connections with the required quality of service, but they lack scalability for additional machines.
The problem was resolved instantly by installing a BlitzFunk system consisting of one access point and four clients: with one client on each bridge crane, the application could be run without restrictions within the specified latency budget. With four clients, the maximum one-way latency between the access point and a client is 10 ms. For inter-crane communication from client to client, latency remains below 20 ms. Each client has a data rate of 1.5 Mbit/s in each direction, more than sufficient to exchange cyclic control messages. Commissioning was seamless. Since the access point is powered via Power-over-Ethernet, only a single cable had to be installed. Thanks to the wide supported voltage range and the low power consumption of the clients, existing power supplies on the cranes could be used. Finally, the BlitzFunk system was configured with just a few clicks, and the cranes were online in two minutes. No adjustments or configuration changes were necessary on the application side.
The cost of this system is €1750 for the access point and 4 × €1100 for the clients, totaling €6150 only. Commissioning and configuration is done in just a few minutes, eliminating additional support costs. Unlike cellular solutions, there are no recurring costs due to licenses, neither for the infrastructure nor for the radio spectrum used.
With BlitzFunk, Demag is able to implement the retrofit of its bridge cranes in a cost-effective way. The requirements for latency and reliability are fully met, ensuring smooth and efficient synchronization between cranes. Setup and operation require minimal effort. The project demonstrates the benefits of BlitzFunk for scalable industrial real-time applications.
“For the highly synchronous control of cranes, we need reliable communication with guaranteed latency. With BlitzFunk, we have found a cost-effective wireless system that meets all technical requirements and can be easily integrated.”
