History comes aliveRed, orange, green, and purple colored lights imbue the corridors with a surreal ambience; hidden machines emit a ghostly rattle from behind closed doors. Visitors listen to their guide, recounting the history of this building that was originally an exhibition hall and once served as a gas power plant for the Bochumer Verein corporation. Today, it is used as an events center. The story is accompanied by video and still images projected onto the unplastered walls – possible thanks to Siemens technology.
The basement of Bochum’s Jahrhunderthalle, with its extensive network of supply tunnels, provides an authentic experience of its industrial history. A key element of the atmospheric setting, alongside audio and video installations, is a multi-colored light show – for which the venue’s operators use SIMATIC S7-1200 to precisely direct and control the illumination.
As part of a two-month final graduation project, four electrical engineers in training from the Technische Berufliche Schule 1 – a vocational technical college in Bochum, Germany – modified and upgraded the existing installation. The prior, somewhat static installation offered little in the way of control options. As project team member Kai Bürger explains: “Our aim was to find a low-cost, uncomplicated way of making the guided tours through the underground tunnels more interesting, with added flexibility to offer different types of tours. The controls needed to be user-friendly, and wireless.”
“Another issue was the, in some places, dusty and damp environment. Thanks to the compact design of the controller, we were also able to retain the complete control cabinet.” The control cabinet houses the DMX controller to control the lights, the MP3 players with sound files to produce the machine sounds, as well as the video players. They only had to be reprogrammed.
SIMATIC S7-1200 Basic Controller with a 1214C CPU was expanded with an SM 1223 digital signal module, an SM 1232 analog signal module, and an SB 1222 digital signal board. The freely programmable web server also impressed the trainee engineers. Bürger’s colleague Darius Skopp, for example, was able to create an HTML website that tour guides can access on a tablet or laptop. A wireless access point at the tunnel system tour’s central area enables guides to execute all control actions on the go.
Other control components include two permanently installed touch-activated SIMATIC HMI KTP400 Basic Panels at the beginning and in the middle of the tour route, as well as various local pushbuttons. These can be used to dim lights or project historical photos onto the wall at one station, or illuminate different areas of the space by moving spotlights at another, for example. Timer functions in the PLC program provide safety features, among other benefits: “When the guide has moved the spotlight to one position at the press of a button, for example, he or she has to wait three seconds before the next movement can be initiated with the next button, so as to protect the lighting units against operator error.”
Any new types of tour or lighting scenarios can be easily programmed with the SIMATIC S7-1200.Kai Bürger, a soon-to-be qualified electrical engineer of the Technische Berufliche Schule 1 in Bochum, Germany
Progress based on technologySIMATIC S7-1200 controls the electrical circuits by way of switching contactors, and it controls the audio and video systems via digital outputs. The SIMATIC controller communicates with the DMX controller via the analog output module: The lighting control converts into digital values the different voltages initially outputted by the PLC as analog signals, to which the trainee engineers have assigned various commands and lighting moods.
“It’s a one-way communication system,” Bürger explains. “The PLC transmits, the DMX controller executes and operates the LED lamps.”
The team of engineers was impressed by the value for the money offered by the KTP400 Basic Panels, as well as by the ability to program error messages in plain text – all seamlessly integrated into TIA Portal. For example, at the start of the tour the guide selects one of three programmed tour types, featuring different lighting scenarios, on the first touch panel. In addition to the default program, there is also a highly dynamic variant featuring frequent color changes and a chaselight sequence, as well as a program with reduced lighting levels allowing the guide to conduct the tour using a headlamp. The new features represent a major advance over the previously employed static lighting of the standard tour.
Bürger is also impressed by SIMATIC S7-1200. “Any new types of tour or lighting scenarios can be easily programmed,” he comments. “The program modules are easy to copy, and by changing voltage values for the various outputs a new configuration for a new tour can be created.”
Integration into the in-house network
SIMATIC S7-1200’s Profinet interface also enabled the team to easily integrate the control cabinet systems into the existing IT network. This means that a member of the in-house technical staff does not have to go down to the basement on each occasion to carry out administrator tasks, as there is now convenient access to the control system from the office workstations. The PLC’s security features also provide a tiered access and password protection system, for guest guides and administrators.
This special project has also been of great benefit to the electrical engineer trainees themselves. Bürger concludes: “As well as enjoying good support from Siemens, we were able to gather lots of practical experience and gain valuable PLC know-how.”
Note on industrial security:
Appropriate security measures (e.g., network segmentation) must be taken to ensure secure operation of the system. Find out more about industrial security.