Der Ingenieur der Wasser- und Schifffahrtsverwaltung 03.07.2015, Author Dipl.-Ing. Annette Horneber
The Hamburg Port Authority is responsible for flood control in the Port of Hamburg. Its responsibilities include operation of the Billwerder Bucht flood barrier. This has recently been equipped with new automation technology. Based on successful experiences, the selected solution has since established itself as a standard in other installations also. The determining factor in this decision was the saving in engineering costs.
With a length of 145 meters, the Billwerder Bucht flood barrier is one of the largest in Germany. It links the district of Rothenburgsort with the Kaltehofe Island in the River Elbe and protects not only the port facilities and adjacent industrial areas, but also a power plant. The flood barrier consists of two rows of barriers, each with four sections or "gates". Each of these sections is moved and held in place by means of two hydraulic cylinders. The gates are 30 to 35 meters long and 13 meters high and have a total weight of 1,600 metric tons. When there is a threat of flooding, they can be lowered within minutes – also independently of one another – and can subsequently be raised again. Four sets of pumps move 55,000 liters of bio-oil for this purpose.
The system was expanded in 2002 and equipped with new hydraulic and control technology. However, even before the usual innovation cycle of 15 years had expired, the control technology in use could no longer be maintained in a satisfactory manner. "It was very convenient for us that Siemens was launching a new generation of controllers on the market at precisely that time. With the migration to Simatic S7-1500 and TIA Portal, we are now relying on the latest technology and can at the same time expect a long service life without any change of system. This argument was extremely relevant to the decision, because every change of system brings with it the risk of increased engineering overheads", explains Michael vor den Brocke, Project Manager at the Hamburg Port Authority (HPA).
Advantages in the engineering phase
The operating personnel were already familiar with the predecessor of S7-1500 – the Simatic S7-300 series – from other applications. Vor den Brocke reports: "We carried out the first tests there with the S7-1500 and were pleasantly surprised at how easy it was to transfer programs from the S7-300 to the S7-1500. The whole operation took just a few mouse clicks. Within just ten minutes, the migration had been successfully completed – we could see that from the identical flashing rate of the modules." It was a different matter for the two line controllers for the barrier, however. These originated from another manufacturer, had incomplete documentation and could not be read. For this reason, they had to be completely reprogrammed. Vor den Brocke saw an advantage in this: "It meant that we could utilize the full functionality of the TIA Portal and achieve a considerably higher programming quality."
Not least due to the volume of shipping traffic, extremely high demands are made on the operational safety of the flood barrier. The line controllers therefore have to process a vast number of safety requests and communicate them to one another. For this purpose, they are interconnected by means of Scalance Profinet switches with redundant power supplies. "At 70%, communication tasks represent the lion's share of control tasks", estimates vor den Brocke. He continues: "When setting up the data blocks with the numerous variables, the bulk processing functions of Excel integrated in STEP 7 saved us a great deal of time." The autofill function operated by holding down the mouse button enables whole series of variables to be set up – quickly and without any errors. Even the user-defined, individually created data types helped to save time during configuration and commissioning: They are set up globally in the project and they do not need to be copied, but simply called up in order to be reused. One-off changes to these data types are automatically and consistently tracked throughout the entire project. The consistent use of data types – as transfer parameters, or for the definition of data blocks – made it possible for the HPA to avoid errors and save engineering time.
Software supports teamwork
As is their usual custom, Michael vor den Brocke and configuration engineer Patrick Beisel shared the topics of control programming and HMI configuration. TIA Portal optimizes this frequently practiced division of labor with the device-proxy function. This enables projects from two different computers to be merged into one project. The integrated change tracking makes it easy to consistently maintain the sequence of the combined project. During commissioning, the simple online/offline comparison proved useful. This meant that there was not a single system standstill – a pleasant surprise for vor den Brocke and Beisel: "I have never known a commissioning process to run as effortlessly as with TIA Portal and Simatic S7-1500."
Safety takes priority
The CPU 1515 was chosen for the lines of flood barriers. Vor den Brocke: "We will also use this CPU as a standard for other tasks. To keep the cost of spare parts storage as low as possible, it is worth keeping the number of versions to a minimum, even if this means the solution is over-dimensioned in some cases." If in future the sluice controllers are also converted to Simatic S7-1500, the experts will switch to the failsafe S7-1500F. This is suitable for both standard and fail-safe solutions and thus covers the entire spectrum of tasks. The requirement for using fail-safe controllers in order to comply with the machine directive only takes effect for existing plants if significant changes are made. Vor den Brocke emphasizes: "Whatever happens, we are relying on fail-safe technology for the sluices and thus pre-empt possible future requirements, because safety and transparency have the highest priority for us."
An integrated solution proves its worth
Even the launches, ice-breakers and survey vessels in the Port of Hamburg are gradually being upgraded to S7-1500. They are also using Simatic Comfort Panels which are dimmable – a condition for use on board ships – and are very well received by the ships' personnel.
For smaller applications, such as water level measurements and displays, the configuration engineers value the robust Siplus version of the Simatic S7-1200 Basic Controller. This functions as an analog value calculator and controls the large display panels along the river Elbe by means of Profibus. Vor den Brocke confirms: "What is of particular interest here is the integrated web server via which other users, such as the meteorological office, can also obtain level readings directly." When any levels are exceeded, the controller notifies the responsible authorities by means of e-mail or text messages. In this way, Simatic Controllers at many locations make a contribution to safety in the Port of Hamburg. "We value the technology because of its robustness, but above all because of the efficient engineering in the TIA Portal – since this really saves us money", says vor der Brocke, justifying the decision for this system.