Luxury wellness spa pampers with PLCs

A five-star hotel on Germany’s Baltic coast is using high tech industrial controllers from Mitsubishi Electric to run its luxury spa and wellness centre.

Whilst ordinary saunas can get by with just a few switches and a three-point temperature controller, modern spas need sophisticated control systems and operating terminals. At the spa centre of the Yachthafenresidenz Hohe Düne hotel, state-of-the-art control systems unobtrusively help to create a stylish atmosphere and enhance the wellbeing of the discerning guests. 

The Yachthafenresidenz at the entry to Rostock’s harbour has its own marina with moorings for 750 vessels, 368 rooms and suites, six restaurants, five bars, its own shopping mall and a congress and conference centre for events with up to 700 participants.

The wellness centre offers guests a wide selection of saunas; steam baths, massage jet showers and an ice machine provide invigorating alternations between heat and cold. Aromas, light effects and music complement the experience. The control systems work unobtrusively in the background to keep all the spa equipment and facilities operating perfectly. The system monitors the fully-automated Jacuzzis and hydro-massage jet showers, regulates the humidity and temperature of the various saunas and baths, controls the steam generators, ventilation fans, water and aroma pumps, adjusts the electric heating and hot water supply system and even takes care of providing suitable mood music and lighting, complete with impressive sound and light effects.

All the control systems were delivered by GridControl of Ruhpolding, a specialist in  software for process visualisation and control in spas and wellness facilities. Proprietor Frit Grübl explains: “The key components of the automation system are the PLC (programmable logic controllers) and their control terminals. We source these from Mitsubishi Electric.

Normally with spa projects, the team only has four to five weeks to prepare and install the fully configured and equipped switchgear cabinet on the construction site or on a cruise ship. Co-ordination is vital and efficient delivery of equipment from Mitsubishi is a pre-requisite.

Before the finished switchgear cabinet is delivered the staff first perform a comprehensive quality test. “Every single function is exhaustively tested before an automation system leaves our premises,” emphasies Grübl. Any failure – for example a failure at sea on a ship system – could be very expensive for the company. “If a big spa system has to shut down even for a single day that can generate damages claims of €20,000 or more.”

Modular control systems

The GridControl engineers chose the modular MELSEC System Q as the foundation for the control systems to be installed the Hohe Düne’s multifunctional spa. This versatile programmable logic controller (PLC) is the most powerful model in the Mitsubishi Electric range; among other things, it can accommodate up to four different processor modules on a single backplane.
“This was necessary because of the very large number of inputs and outputs,” says Grübl. With earlier systems GridControl has tended to use the more modest FX series.

The operator of the hotel in Rostock opted for a centralised system with conventional wiring that would allow all functions to be controlled easily from a single location. Nearly 200 outputs had to be connected so that the controller could switch all the spa systems, which range from the heating and steam generators for the saunas and baths to water and aroma pumps, ventilation and lighting systems.

Thermometers were installed in 64 locations throughout the complex to measure the temperatures. Other sensors measure the humidity in the saunas and steam baths. Pumps, fans, steam generators and other devices are connected via digital inputs and outputs to the controller, which automatically registers status and error messages.

Like all Mitsubishi Electric’s compact and modular controllers, the System Q PLC is programmed under Microsoft Windows, using one of two software packages: the modern GX IEC Developer (European IEC 61131-3 standard, Function Block, Ladder Diagram, Instruction List, Structured Text and Sequential Function Chart languages), or the popular GX Developer (Ladder Diagram, Instruction List, Sequential Function Chart). “The modular software architecture and the well-matched components enable us to develop a customised control console for a system very quickly,” says Grübl enthusiastically.

An intuitive user interface was a top priority for the developers. In addition to this the interface and the control terminal had to have an attractive design to match the exclusive setting. GridControl chose a control terminal from Mitsubishi Electric’s new E1000 series for operation and visualisation of the spa systems. The E1071 terminal has a high-resolution TFT (thin film transistor) liquid-crystal display with a diagonal width of 6.5” and a touch screen interface. It is an extremely slim unit with a minimal installation depth.

The control terminal is installed in the reception are of the spa, giving the staff there direct access to all the system’s functions. The multi-lingual menu intuitively guides the user through the individual levels and components of the spa systems. Photos, graphics and floor plans provide visualisations of the sauna cabins, steam baths and showers, along with all the individual components and their functions.

All messages and alarms can be confirmed on-screen and can also trigger automatic emails, SMS text messages or faxes, which are sent by the controller via a connected modem. For example, if the aroma fluid in a steam bath runs low the controller automatically sends an order to the supplier. The new canister of fluid arrives in time, without any action being required on the part of the hotel staff. Remote access to the controller is equally simple – the staff at GridControl can check the status of the entire system from their.

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