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With a production budget topping €10 million, The Wyld is the most extravagant performance currently to be found at any venue in Europe – but the Friedrichstadt-Palast in Berlin is not just any venue. Home to the largest theater stage in the world, it also features the most sophisticated movable stage technology. Working behind the scenes to keep the performers safe, 67 safety controllers comprise the most complex application ever built on the basis of openSAFETY.

Source: Soenne

The latest production of Berlin's famed Friedrichstadt-Palast tops anything that has ever been seen on the stages of Europe. The historic venue – also known as "Europe's Show Palace" – spared no expense to ensure that The Wyld - Out of This World is as spectacular as its name suggests. The €10 million invested in the show is a sum that even legendary Broadway theaters can only dream of. Judging by ticket sales, the investment has paid off. More than 130,948 tickets had been pre-ordered before the show's premier on October 23, 2014, and less than four months into the season, ticket sales for The Wyld had exceeded the 250,000 mark.

Records broken on stage and in the ticket booth are not all The Wyld has to offer. While the theater enthusiasts among you may know that "The Palast" is home to the largest stage in the world, you may not be aware of another record broken off stage. Well hidden behind the scenes, a network of 67 safety controllers comprise the world's most extensive safety installation based on openSAFETY and network-based safety technology from B&R.

A safe transformation

This cutting-edge safety technology ensures that the performers can safely rely on the 55 motorized platforms that transform the stage over the course of the show, at times even forming steps.

To do this, the safety controllers read signals from pressure-sensitive safety strips installed around the circumference of each step. If a performer comes in contact with the edge of a moving platform, this system ensures that the platform and associated step elements are halted immediately. This reaction must take place extremely quickly since the platforms are raised and lowered up to 170 millimeters per second by a ballscrew scissor lift driven by an AC motor.

Each step has a dedicated programmable controller called a "Stage Mover". Developed and built by stage technology specialist Gietec in close cooperation with B&R, the Stage Mover controls the electric drive axis and evaluates the signal from the safety strips. In a single rack-mount housing unit, it combines all the elements needed to control the movement of a single electric axis.

In Europe's most expensive stage production – – movable platforms safeguarded by openSAFETY transform the stage and bring the stars into position. (Source: Robert Grischek)

Drive modules with integrated safety

At the heart of the Stage Mover is an energy-efficient X20CP1583 PLC with a POWERLINK interface and integrated I/O modules from B&R's X20 system. The PLC is accompanied by a digital SLX410, which, in addition to its safe inputs and outputs, also performs the functions of a safety controller. With the PLC's integrated POWERLINK interface communicating with the higher-level controls, Gietec's engineers added a separate X20 POWERLINK interface module for the ACOPOSinverter P74 inverters. This internal POWERLINK bus reduces the load on the command bus to the higher-level controls. The encoderless AC motor that drives the scissor lift as well as the draw-wire encoder and limit switches on the stage elements are incorporated via a Harting multiconnector. The only other connection to be made is the 400 V mains power cable, and the stage elements are ready for their performance.

"You don't get a modular design like this without some extra effort," notes Gietec's founder and managing director Georg Schosser. "But this way, at the end of the season, we have no problems using the Stage Mover to solve completely different drive requirements in other shows."

In addition to the Stage Mover for electric axes, there is also a variant for controlling the hydraulic or pneumatic axes that also contribute to extensive range of dramatic staging effects present in The Wyld.

Working closely with B&R, Gietec developed modular, networked controllers with integrated safety technology to control electric, hydraulic and pneumatic axes. (Source: Gietec)

Since the fall of 2014, Berlin's Friedrichsstadt-Palast is home to the most complex application ever built on the basis of openSAFETY and POWERLINK. A total of 67 SafeLOGIC controllers, connected via a single POWERLINK backbone, ensure safe operation of movable platforms and other stage elements with a cutoff time of 10 milliseconds.

One software project for three hardware variants

The control head containing the safety controller and safe I/O modules is identical for all three variants. The only difference in hardware are the components required to control the different types of axes and the X20 modules used for standard communication. "Although our Stage Movers have a variety of hardware to support the different axis types, we're still able to manage it all in a single software project," says Schosser. "That makes the system easier to set up and the software more efficient to update and maintain. It was a key argument in favor of B&R's solution."

For Gietec, the application hinged on two decisive criteria: the short response times that could be achieved with network-based openSAFETY communication and the complete flexibility offered by the SafeLOGIC safety controllers. "Conventional hardwired circuits would have given us response times of around 500 milliseconds, which is just not enough to guarantee safety on stage," notes Schosser. "Even given the daunting task of monitoring signals from 55 safety strips as well as various other safety equipment, B&R's solution delivers response times of about 10 milliseconds – more than enough to satisfy safety standards now and into the foreseeable future."

"Conventional hardwired circuits would have given us response times of around 500 milliseconds, which is just not enough to guarantee safety on stage," notes Schosser. "B&R's solution delivers response times of about 10 milliseconds – more than enough to satisfy safety standards now and into the foreseeable future." Georg Schosser, Managing Director, Gietec GmbH

Two identical, multi-purpose Stage Controllers from Gietec, based on a Panel PC 900 with a projected capacitive 24" touch screen serve as control consoles for the 55 movable platforms that transform the stage during every performance of . (Source: Gietec)

67 networked safety controllers

The safety controllers in the 60 Stage Movers used at the Friedrichstadt-Palast are coordinated by a cascade of 7 master safety controllers from the SafeLOGIC family.

Despite the huge volume of data to be managed on the POWERLINK backbone, Gietec was able to do without a cascaded bus architecture, which kept the number of components and cabling effort to a minimum.

For master control of the system, Gietec developed the "Stage Controller" – based on a B&R Panel PC 900 with a projected capacitive 24" touch screen. All application software for this multi-purpose control console, including the HMI application and Stage Mover software, was developed using Automation Studio. The Friedrichstadt-Palast uses two Stage Controllers – one dedicated to HMI and the other controlling the stage elements – connected via B&R's SDL3 digital display transmission technology.

"B&R provided exemplary support throughout this project," commends Schosser. "As usual, we were able to contact B&R's well-trained support team, who have the admirable quality of working to find real solutions rather than offering up half-baked speculations."

The management and guests of Friedrichstadt-Palast have been more than pleased with the results so far. And for all The Wyld shows to come, in the name of openSAFETY, we offer the performers the traditional blessing with a twist: "Don't break a leg!".

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