When the Port of Virginia needed to expand the Virginia International Gateway facility with 86 automated-stacking cranes (ASCs), it was the largest single ASC project ever initiated by a port. Not only that, but the Port needed operators to work from a centralized control room, using advanced sensors, video, and displays.
My October 2021 article on Automation.com, co-authored with Michael Cooper and Matt Mandros of TMEIC and titled, "PLC and Operator Interface Advantages Stack Up for a Large Container Automatic Stacking Crane Project," describes how Emerson PLCs and HMIs delivered the required robust and scalable remote control capabilities. Integration was carried out by the TMEIC Corporation (Toshiba Mitsubishi-Electric Industrial Systems Corporation), a firm with extensive history in this field, and with previous experience implementing Konecranes at this site.
Super-sizedRail-mounted gantry cranes move in three axes to hoist and transfer shipping containers among ships, storage yard stacks, rail cars, and truck trailers. The containers are 40 feet long, and can be unevenly loaded up to 40 tons, yet they need to be captured and landed by large equipment with an accuracy of just 50mm. Older cranes were controlled by line-of-sight operators stationed in crane-mounted cabs.
Modern ASCs use extensive automation to improve the safety and accuracy of this work. For this project, an Emerson PACSystems RX3i PLC mounted on board each crane serves as a local crane management system (LCMS) for monitoring sensors and controlling motors. Each LCMS PLC communicates with nearby cranes to avoid interfering with each other. The crane PLCs also communicate with centralized yard director and remote operator station PLCs to coordinate the overall work, and to allow any operator to control any ASC. A software-based terminal operator system organizes and schedules all movements.
Advanced integrationPC-based HMI software provides visualization, and each ASC runs a standalone PC-based HMI to provide local visualization at the ASC. A sitewide view is provided with the same HMI software configured in a supervisory control and data acquisition (SCADA) role. The HMI/SCADA also historizes data, and it provides both centralized and remote alarming.
Intelligent LIDAR-based sensors and variable frequency drives communicate directly with the crane PLCs to provide the required high-accuracy and responsive distance information, and associated control of crane motion. High-performance networking is crucial so that operators can execute low-latency control of crane operations when needed. In addition, the cranes need to interact with higher-level systems to identify idle cranes, assign the next available operator to the next crane, and select the proper camera views. Many crane movements are executed automatically.
As the number of ASCs and remote operator stations scale up, the cross-connection and bandwidth challenges become exponentially more complex.
Not only are many more combinations possible, but there can be many more connections active in parallel at the same time. Fortunately, the latest PACSystems RX3i PLC hardware, software, communications protocols, and networking media were up to the task.
The first generation of ASCs at the Port used PACSystems RX3i PLCs, which still serve reliably today after many years of service. For best interoperability, the natural choice moving forward was to select the newest generation of Emerson’s robust PACSystems RX3i PLCs. Emerson technologies are providing a high-performance solution today, are compatible with existing systems, and enable future capabilities – such as ‘big data’ aggregation and analytics – to drive additional efficiencies.
Figures all courtesy of Emerson or Port of Virginia