PC-based control simplifies building revitalisation
December 2018, System Integration & Control Systems Design
PC-based building automation from Beckhoff is characterised by its openness, reliability, ease of use and long-term product availability. In the revitalisation of the Eurotheum high-rise building in Frankfurt, Plüderhausen-based system integrator Herrmann & Co. benefited from these features in several ways. Having implemented the building’s original automation platform and smoke extraction system in 2000, the SI was able to upgrade it substantially in 2018 with minimal effort in terms of time and technology.
At 110 metres tall, the office and hotel complex stood out from the beginning due to its size and extremely flexible leasing options. While eight floors plus the lobby are occupied by a hotel with conventionally automated building operations, 21 of the 31 floors can be subdivided based on the tenant’s needs and leased in units of 240 square metres or larger. Available layouts include open concept floor plans, office setups with rooms or cubicles, or a combination of the above. Essential for the flexibility of use is easily adaptable room control for building services such as heating and cooling and lighting and shading, enabling customised floor layout with little effort. Hansjörg Ludwig, general manager of Herrmann, explains the original requirements: “Room sizes and floor layouts had to be modifiable within a specified timeframe. We accomplished this by establishing a 1.35 metre grid based on the width of the windows that allows each segment along a window axis to be flexibly assigned. This flexibility made it possible to achieve the original tenant’s goal of being able to configure e.g. three single offices or a single conference room in the same space and within 24 hours.”
Flexible building automation makes all the difference
“Besides reconfigurable room walls, such a building requires highly flexible automation systems, says Herrmann team manager Rainer Daiβ: “The infrastructure endpoints for HVAC control stay in place, as do all the sensors and actuators, blinds and the lighting control elements. The building operator, however, must be able to modify the interaction of these data points with higher-level building controls, and this can be accomplished via a user-friendly configuration tool in the central building control system. In addition, the advanced single-room controls feature three operating modes set for comfort, economy and night operation. The rooms are controlled automatically, depending on the time of day and the presence of occupants determined via occupancy sensors, but can all be individually adjusted as well.”
Ludwig adds: “We used Beckhoff products in the Eurotheum from the start and have been particularly impressed by the system openness of PC-based control. Due to a requirement of the original tenant, however, we had to implement most of the automation systems with third-party Interbus components at the time. When the leasing relationship ended, the Eurotheum was to be fully renovated, which enabled us to implement all automation components with PC-based control technology from Beckhoff. We started in 2016 with a total renovation of the smoke extraction system. This was followed by a floor-by-floor renovation of the entire building as leases permitted.”
Michael Herrmann, assistant technical manager at Herrmann, confirms the success of this approach: “As part of the modernisation project we installed state-of-the-art building technology over the last two years. Due to the modular control system from Beckhoff, configuration of the building is now much more flexible.”
Revitalisation improves reliability and protects investments
Herrmann opted to implement Beckhoff IPCs from the start. Daiβ explains the rationale: “Back then, we decided to use C6130 control cabinet PCs, because they were the only devices with enough computing power for the variable room automation we needed. No PLC system with comparable performance was available back then. In addition, only IPCs could be equipped with plug-in cards as interfaces for the various bus systems used in the building. To connect the more than 40 000 data points in the building control system, 20 C6130s were distributed across three floors. Today, 20 compact C6915 control cabinet PCs perform this job. Since they are much smaller, they could be distributed across the individual floors in a more space-efficient manner with a floor manager on each floor. We benefit from the continuous advancement of control technology from Beckhoff while still being assured that components will be available for the long term. Even the originally installed C6130s are still available.”
Another major factor in the building revitalisation project, says Herrmann, was the high flexibility of PC-based control: “It provides a comprehensive toolbox that helps us implement all specific requirements of a building quickly and with minimum effort. We can integrate legacy systems that are still in good working order and carry out revitalisation projects without having to interrupt building operation.”
The same applies to the TwinCAT automation software, adds Daiβ: “No comparably flexible software system was available at the time. It also offers the benefits of efficient engineering and upward compatibility, which is critical for long-term operational reliability. The Eurotheum revitalisation is a prime example because we were able to transfer the almost 20-year-old control software to the new IPCs without having to make any changes, except for a few adjustments that had become necessary due to architectural modifications. This is a huge benefit for us as a system integrator.”
Ludwig considers long-term availability and reliability to be important arguments for upgrading the I/O system as well: “Some of the legacy Interbus components had been discontinued, which can cause problems, particularly in commercial buildings that are designed for many years of use. In addition, many I/O components were installed in ceiling-mounted distribution boxes. In the past, this frequently created problems when components worked themselves loose. As a result, the already sensitive Interbus communication broke down frequently. When this happened, technicians spent too much time looking for fault locations when the fix involved nothing more than fastening a loose terminal connection. Since the EtherCAT and bus terminals from Beckhoff snap into position much more securely, those problems are now in the past. In addition, the extensive diagnostic capabilities of the EtherCAT system make it much easier to find exact points of failure.”
EtherCAT for smoke extraction and building automation
The complexity of Eurotheum is reflected in its many physical data points, after the revitalisation: 100 000 for the building automation and an additional 6000 for the smoke extraction system. Accordingly, having powerful data communication capabilities is critical according to Daiβ: “The huge volumes of data generated require an exceptionally fast and reliable bus system like EtherCAT that can operate over copper wires just as well as over fibre optic cables, depending on the circumstances. Especially for the highly available smoke extraction system, EtherCAT stands out with its easy-to-implement cable redundancy and fast installation. We were able to upgrade all 30 control cabinets, each of which has two substations, in only two months. This was particularly important in terms of fire protection, because when the smoke extraction system was switched off for the modernisation in ongoing building operation, a firefighter had to be stationed on each occupied floor as a costly safety measure.”
The smoke extraction system is controlled by two CX2030 embedded PCs. They connect two separate EtherCAT loops that run through all building floors. The system employs a total of 74 EK1501 EtherCAT couplers along with 450 EL1008 digital input terminals and 150 EL2008 digital output terminals. Based on the information supplied by these components, the smoke extraction system is able to identify one of approximately 50 smoke extraction scenarios and will accordingly turn the appropriate exhaust fans on or off and open or close fire dampers. To do this, the Beckhoff control system communicates with the building management system over an OPC server via ADS.
Data transmission for the room automation systems for each floor also runs over an EtherCAT loop that connects the four switching panel alcoves as interfaces to the individual systems. Each of the 20 floors has 34 distribution racks and 38 BK1150 bus couplers to handle the typical building data via M-Bus, KNX, Dali and DSI, as well as the legacy Interbus network for the HVAC system. In addition, each floor has 15 EP2008 I/O box modules linked to an EtherCAT loop that are used to control the heating valves in a particularly space-saving manner.
For more information contact Michelle Murphy, Beckhoff Automation, +27 11 795 2898, email@example.com, www.beckhoff.co.za