Airport Berlin Brandenburg

Airport Berlin Brandenburg

Apron drainage with BACnet: cost-effective and fail-safe

Berlin Brandenburg Airport uses an extensive infrastructure to manage rainwater over an area of almost 1,500 hectares. In order to reduce costs in the apron drainage process network and make the system more fail-safe, the operators rely on gateways from MBS GmbH.

The new Berlin Brandenburg Airport, which will handle all of the German capital's air traffic in future, is currently being built at the Schönefeld site. Its area has been expanded by almost 1,000 hectares, which is equivalent to around 2,000 soccer pitches. An extensive sewer network with pumping stations, retention basins and treatment plants ensures that rainwater is collected, treated and drained away.

Data of great relevance is collected in the apron drainage process network. For example, heavy rainfall is closely monitored. In addition, the level of TOC (total organic carbon) in the surface water is continuously measured so that this information can be regularly passed on to the environmental authorities.

Simplify processes with BACnet

Technically, the process network is based on the Siemens automation system Simatic S7-300 PLC with industry standard Profinet (Process Field Network) and fieldbus standard Profibus. The S7-300 was not to be replaced, as it works stably as a reliable controller. The data was collected by an OPC server, which transferred it to a SCADA system. Now the Windows servers were due for an upgrade, which would also have made it necessary to update the SCADA server.

To reduce costs here, Gunnar Hemmerling, building automation engineer at Schönefeld Airport, wanted to convert the automation system to the BACnet (Building Automation and Control Networks) communication protocol. To date, the apron drainage system was the only automation level at the airport without BACnet. However, BACnet is the key to simplifying and standardizing the various stakeholders at the airport. Until recently, 12 different BMS systems with different bus systems were connected in the technical control center. Digitization in this heterogeneous design was unthinkable. The airport therefore adopted a BACnet factory standard and set itself the goal of using only 2 BMS systems in the control center in the future.

 Reduce expenses

BACnet has already proven itself many times over in the airport's building automation system. The operator, Flughafen Berlin Brandenburg GmbH FBB, not only benefits from the integration performance of the BACnet protocol. It also saves time and effort by networking the devices via the existing IT instead of wiring them. Hemmerling: "BACnet offers independence when it comes to IT security, plus greater scope for data management and utilization."

Based on his positive experience with the gateways from MBS GmbH, Hemmerling purchased the Double-X I Universal Gateway Profinet with 1,000 data points for the 13 pumping stations after a detailed discussion with the Krefeld BACnet experts. It serves as a communication interface between different bus protocols. With an integrated protocol hardware adapter, it converts the Profinet standard into the open BACnet bus protocol.

Gateways as communication interfaces

Configuration is carried out using text files that are transferred to the gateway via a browser using an integrated web server and stored there permanently. "Our products can be flexibly adapted to changing requirements," emphasizes Nils-Gunnar Fritz, Managing Director of MBS GmbH. "The firmware of the microprocessor used is also currently being updated so that even more data points can be mapped in the future via memory multiplexing."

Pump station by pump station, the process network was converted to BACnet during ongoing operations in 2018/2019. The fact that the new head of the building automation and control center technology department purchased a powerful BACnet MBE (management operating device), enteliWEB from Delta Controls, played into the hands of the technology team. It is web-based and combines a visualization interface with an easy-to-use energy management tool. There is also an automated interface to the ticket system in the control center, so that the digital data from the automation stations is now sent directly to a tablet for the workshop employees via BACnet in order to quickly manage operation and fault clearance. Hemmerling: "This was a great incentive for us: while the BACnet-capable wastewater process network had already been converted to enteliWEB, we first had to convert the S7-300 to BACnet for apron drainage, set up the process network accordingly and supply it with data points."

Interoperability for a wider range of products

The mass of 7,000 data points for apron drainage alone initially proved to be a stumbling block. "When working with Profinet, the challenge is to follow the sequence meticulously," explains technician Sven Nachtigall. "If there is just one mistake, you may have to start from scratch." In the end, Nachtigall also opted for this approach. Once the coupling was successful, BACnet objects, properties and trend logs were created and the BACnet factory standard was implemented. Finally, the old system images were quickly recreated in the new MBE.

The apron drainage process network now consists of the Siemens S7-300, which provides the necessary stability for the automation level, and the powerful MBE enteliWEB from Delta Controls. As an interface, the Double-X I Universal Gateway Profinet offers all the advantages of the BACnet world of building automation. "Thanks to their interoperability, BACnet and the MBS products provide us with a wide range of products," says Hemmerling.

Costs halved

In addition, data communication is now much less complicated. New data points are no longer added in the SCADA system, but are set up in the gateway, converted to BACnet/IP and saved directly in enteliWEB with an updated system image. If communication should ever come to a standstill, there is only one interface - the S7-300 / Universal Gateway link, which can be checked directly. In the past, if there were network failures, the important data was lost. Today, in such a case, enteliWEB automatically retrieves its input from the gateway, which stores trend log data in a buffer and makes it available as soon as the network is active again.

The project is also more than satisfactory in terms of costs, as the price of the SCADA update would have far exceeded the cost of purchasing the gateways. "Compared to the estimated costs that would have been incurred with our old solution, we have saved 50 percent," Hemmerling calculates. At the same time, there is now a standardized infrastructure that can be easily expanded if necessary.