Efforts to maximize the performance, speed and safety of the next generation of luffing jib tower cranes has resulted in the development of specific programmable logic controller (PLC) features, along with the supply of variable speed drives with FSO safety modules from ABB.
Recom Srl is a world leader in luffing jib tower crane technology based in Belluno, Italy. Mariano Moritsch, managing director of the 50 year company, comments: “The main challenge facing our industry is reaching mega heights - closer and closer to 3200 feet - but with maximum safety. Our cranes are mainly used in downtown areas, where maximum structural and load safety is a critical requirement.”
To achieve higher performance and safety levels at the same cost, Recom's engineers realized they needed to completely redesign the crane’s automation system. The company opted to partner with ABB, which was able to provide a package comprising its AC500-S safety PLC and an ABB industrial drive, ACS880, with an FSO safety module. More importantly, ABB offered an absolute guarantee that the PLCs and variable speed drives would communicate flawlessly with one another. The long-life availability of ABB’s PLCs was critical to meet the 20 year life cycle of Recom’s cranes.
In addition, Recom was given access to ABB’s engineering solutions team and its expertise in crane applications. “ABB offered high availability and flexibility to work with us as a partner and not simply as a vendor,” explains Moritsch. “From the very beginning, ABB and their engineers worked side by side with us to understand our present and future market needs in terms of safety and technology innovation. ABB’s worldwide service and support network was ready to provide us with all the assistance and support necessary for product development.”
Walter De Battista, head of Recom’s hardware engineering department, comments: “ABB proposed that we use AC500-S PLC in this application, which initially was not included in our project. Following this suggestion, we implemented a fully integrated control in the machine. This saved a lot of time thanks to the tips provided by ABB's engineers about software development and industrial drive commissioning.”
Recom’s programmers benefitted from already knowing the IEC 61131-3 programming language, which is used to set-up the PLC software. Also the memory card within the ABB industrial drives enables the application software to be stored. Should an extreme temperature or variable power supply damage the drive, it can be replaced and the memory card inserted to get the crane operational quickly. In the past, the customer could only return the failed drive or buy a new one already pre-set for their application, which was time-consuming to complete.
Crane motors must be fine-tuned to the variable speed drive. The ACS880 ensures maximum control and fine-tuning even with Recom’s custom motors. “Industrial drive settings were fine-tuned iteratively. ABB's engineers visited us several times to help streamline the process, thus proving once again, whenever needed, that they can handle any situations and fix even very minor details,” explain Recom's engineers.
“ABB assisted us during motor testing at our manufacturer's plant and helped us verify that our calculations actually matched motor performance.”
Motor testing is one of the most important aspects that helped develop and strengthen the partnership between Recom and ABB. So far the rotation movement of the crane tower has been driven by DC motors, but the market requires a shift to AC motors and this is why Recom - in collaboration with ABB - is currently developing a dedicated solution based on ACS880 industrial drive.
Increased use of prefabricated and modular components in the construction of high-rise buildings is boosting the demand for luffing jib tower cranes. These cranes feature outstanding reach and require little room for slewing motions - a particular advantage in city locations. The range provides fixed and mobile counterweight for higher performance in constrained space.
Recom's cranes are used worldwide including some significant London landmarks such as The Shard, one of Europe’s tallest buildings, Canary Wharf and the huge Leadenhall Building, also known as the “Cheesegrater”.