Safe automation solution for Palladium Stage Theatre
High degree of flexibility and cost effectiveness
Seeing a show at the theatre continues to be a popular pastime for engaging with culture.
What the audience does not see, however, is the sophisticated behind-the-scenes
automation technology that ensures everybody’s safety. At the Palladium Stage Theatre in
Stuttgart, Germany, a safety solution from Phoenix Contact’s Easy Automation product range
is deployed for this purpose (Figure 1, lead figure).
Figure 1 – Lead Image - View of the Palladium Stage Theatre’s audience area, which has a capacity of approx. 1,800
The Palladium Stage Theatre is located at the heart of the SI Centre, Stuttgart’s biggest
event and leisure destination. The theatre, which was built in 1997, has a two-tier layout with
raked stalls that provide seating for 1,800 visitors. With a floor area exceeding 4,800 square
meters, the Palladium Stage Theatre is one of Germany’s biggest stage venues. Since its
opening, it has hosted numerous well-known musicals including ‘Phantom of the Opera,’
‘Dance of the Vampires,’ and ‘Mamma Mia.’ When the safety components of the automation
technology system were due for an upgrade in 2013, the
solution proposed by engineering firm Michael Heiser –
based on components from Blomberg-based automation
specialist Phoenix Contact – was found to be the most
convincing. On the one hand, this solution is highly
flexible, as the modular I/O stations of the Inline modular
automation system can easily be augmented with
additional standard modules and function modules. On
the other hand, it is a very cost-effective approach, as the
SafetyBridge Technology deployed here eliminates the
Figure 2 - Several Inline and SafetyBridge modules are connected to the
need for a costly separate safety control system
ILC 171 ETH 2TX compact controller.
(Figure 2).
Multiple fire protection measures
In Germany, operation of a theatre venue is subject to
the Federal Regulation on the Construction and
Operation of Places of Public Assembly
(Versammlungsstättenverordnung, or VStättV).
According to VStättV, the theatre operator is obliged to
delimit the stage from the audience area as a separate
fire zone. An iron curtain is used to this end. While the
term ‘iron curtain’ has also come to describe the EastWest political and ideological divide resulting from the
Figure 3 - The iron curtain that separates the stage from the audience area is
Warsaw Pact, in the theatre, this is an established fire
half-lowered.
protection measure. It efficiently separates the stage
and audience areas into two distinct zones. (Figure 3). VStättV also dictates that the iron
curtain must be of such a weight that it takes no more than 30 seconds to descend of its own
accord. At the Palladium Stage Theatre, this protective device weighs more than ten metric
tons.
As well as an iron curtain, the safety measures at the
Stuttgart performance venue include two smoke
extractor hoods located above the stage and the
audience areas. In the event of a fire, the smoke
extractor hoods ensure that smoke gas escapes the
building by convection. The hood installed above the
stage area weighs more than eleven metric tons, which
makes it significantly larger than its counterpart above
the audience area (Figure 4). This is because the props
and materials to be found in the stage area are typically
Figure 4 - The raised smoke extractor hood located above the stage weighs
more than eleven metric tons.
much more flammable than those in the audience area,
which means the smoke they emit, could be significantly more intense and hazardous.
Modbus/TCP for all communications
The automation solution is designed to provide reliable functioning of the three safety
devices described above – one iron curtain and two smoke extractor hoods. According to the
regulatory report, these need to achieve Performance Level D. For this purpose, a risk
assessment according to EN ISO 13849-1 was completed; this is a harmonised panEuropean standard for the implementation of the corresponding machinery directive.
Specifically, EN ISO 13849-1 regulates the design of safety-related control systems in the
context of the machinery directive. Performance Level D, which was deemed necessary for
the Palladium Stage Theatre, is the second-highest requirement level that can be imposed
on a control system. In order to comply with such stringent safety requirements, Michael
Heiser and his team deployed SafetyBridge modules and other terminal blocks from the
Inline modular automation system for inputting all the necessary I/O signals, as well as two
ILC 171 ETH 2TX compact controllers. All of these components are part of the Easy
Automation product range. This eliminates the need for a costly safety control system.
As they represent the core of the automation solution,
the control systems are distributed across two
installation sites – a large control cabinet located next
to a hydraulic pump unit, and a not-so-large distributor
box in the roof space above the stage area (Figure 5).
The two ILC 171 ETH 2TX controllers are connected
via an Ethernet cable and exchange their data via
Modbus/TCP. On an application level, communication
between the two devices is implemented using the
5 - The larger of the two control cabinets houses an ILC 171 ETH 2TX
Modbus/TCP functional modules provided as part of the Figure
compact controller plus connected Inline and SafetyBridge modules, as well
as a Quint uninterruptible power supply unit consisting of a battery, power
PC Worx engineering software package. One PLC
supply, and diagnostic unit.
serves as the Modbus/TCP client, while the other
controller handles the server tasks. The automation solution also includes an uninterruptible
power supply (UPS) from Phoenix Contact’s Quint product range. It ensures that the entire
automation system remains powered for an hour in the event of a power failure. The
parameter data from the UPS can be accessed by the ILC 171 ETH 2TX via an RS232
interface, which among other things means that the backup batteries only need to be
replaced once they have actually reached the end of their service life.
Safety-oriented processing within the SafetyBridge module
SafetyBridge Technology is unique in that its data packets can be transmitted via a standard
bus protocol. As a result, the safety solution is not only independent from the controllers but
also from the network. At the Palladium Stage Theatre, the exchange of safety-related data
packets takes place via a standard Ethernet cable using the Modbus/TCP protocol. This is
possible because the SafetyBridge protocol itself is superimposed over a standard bus
protocol such as Modbus or Profinet. The two ILC 171 ETH 2TX compact controllers do not
handle any safety-related tasks as such but are exclusively used for data transport purposes.
To these Inline controllers, the data coming from the SafetyBridge modules appears like any
other I/O data. It is not identified and processed as safety data but simply copied from one
ILC 171 ETH 2TX to the other. The safety functions are entirely processed by the logic
circuits of the SafetyBridge modules. The Safeconf engineering software tool is used for
configuring the SafetyBridge I/O modules and programming the internal safety circuits.
Considerable force
When specific events such as a power failure or an interruption of the Ethernet connection
occur at the Palladium Stage Theatre, the automation solution responds with a predefined
safe state. The iron curtain is lowered and the two smoke extraction hoods above the stage
and audience areas are opened. The protective devices are raised and lowered using
hydraulic cylinders. A pump unit periodically regulates the pressure required to keep the
smoke extractor hoods open (Figure 6). The piston rod of the large hydraulic cylinder for the
iron curtain moves horizontally (Figure 7). Several deflection rollers are in place to redirect
the force vertically to the iron curtain.
Figure 6 - The pump unit – to the right for the iron curtain, to the left for the
two smoke extractor hoods – provides the compressed air needed for the
hydraulic cylinders.
Figure 7 - When the iron curtain is in its raised position, the piston rods of the
hydraulic cylinder are extended.
While the iron curtain can be lowered within no more than 30
seconds on accord of its own weight, the two smoke extractor
hoods need to be raised, which means their own weight needs
to be overcome as well. For the big smoke extractor hood
above the stage, the two hydraulic
cylinders exert a force of more than
107,800 newtons (11,000 kilograms x
9.8 newtons/kilogram) (Figure 8). This is
only possible through the use of sizable
pressure storage containers. When the
system needs to be put into its safe
state, the valves of the pressure storage
containers move to their safe position
and release the stored pressure to the
cylinders so that the pistons can raise
the smoke extractor hood.
Figure 8 - One of the two hydraulic
cylinders used to raise the eleven-ton
smoke extractor hood above the stage.
Personal judgment
During a show, the head stage technician
has a special role to play in terms of
safety. Although safe states are specified
for occurrences such as power failures,
there is no automatic response for fires.
The automation system does not evaluate
any signals from fire protection sensors
such as smoke detectors. In the event of
a fire, the head stage technician needs to
decide if and when exactly the iron
curtain and smoke extractor hoods are
deployed.
Figure 9 - The pressure storage container
holds the hydraulic pressure needed by
the two hydraulic cylinders to raise the
smoke extractor hood located above the
stage
For further information visit:
www.phoenixcontact.co.uk
If you are interested in publishing this article, please contact
Becky Smith: [email protected] or telephone
0845 881 2222.
Cost-effective automation
solution for small and mediumsize standard applications and
safety applications
The ILC 171 ETH 2TX features
two Ethernet ports and is one of
Phoenix Contact’s 100-series
Inline controllers. These compact
controllers are at the core of the
Easy Automation range of
automation system products. Easy
Automation represents a full-scale
solution for the cost-effective
automation of small and mediumsized applications. Functionally
safe applications can be
implemented through the use of
SafetyBridge modules, which are
part of the Inline modular
automation system range.
Because the safety functions are
processed directly inside the
SafetyBridge modules, there is no
need to also invest in a costly
safety control system.