Planning and Renovation of Stage Control Systems
Stage Control Systems – Overview
The control system is the central element in operating stage machinery. It forms the interface between the operator and the installed equipment.
Modern stage installations often include a large number of electrical or hydraulic drives. All drives must be clearly controlled and safely moved — often during rehearsals and performances, in low lighting, and with activity on stage. It is therefore evident that a stage control system must fulfill numerous demanding tasks.
A stage control system must:
- comply with the high safety standards required for stage operation
- reliably and precisely reproduce choreographed movements
- operate dependably at all times
- enable efficient and economical stage workflows
- support the realization of artistic requirements through the stage machinery
Planning and Preselection
When planning and designing control systems, it is crucial to define the intended purpose of the equipment in advance:
- Is the system mainly used for slow, preparatory work such as stage setup?
- Will loads be moved above people?
- Do several drives need to move one load simultaneously, possibly including performers (as in a flying system)?
Such requirements can be classified using “Use Cases (UC)” described in Annex B of DIN EN 17206. Together with the tables in Annex C, these Use Cases help predefine the equipment specifications for the upper and lower stage machinery as well as the control system requirements.
Additional aspects concern usability and operating comfort, for example:
- How large should the screen be?
- How many control levers are required?
- Is a wireless control panel necessary, or are wired solutions sufficient?
- How can programmed movements be stored and recalled efficiently?
- How can the control system support required expert inspections?
Before renewing or upgrading a control system, it is essential to analyze future requirements and define the Use Cases for each group of equipment.
As a general rule: the simpler the Use Case, the smaller the required functionality — and therefore the lower the cost.
What Is a SIL3 Control System?
The Safety Integrity Level (SIL), defined in DIN EN 62061, describes the reliability of safety-related control functions. There is no such thing as a “SIL3 control system” in itself — rather, each safety function within the system is classified individually.
SIL defines three levels of safety integrity requirements, from SIL 1 (lowest) to SIL 3 (highest). In stage technology, SIL 4 is not relevant. The required SIL level is determined by a risk assessment in accordance with DIN EN ISO 12100, considering frequency, duration, severity, and avoidability of hazards.
Importantly, SIL applies to each safety function (e.g. overload protection, position deviation protection), not to the entire control system. For subsystems and components, the Performance Level (PL) according to DIN EN ISO 13849-1 is used instead.
Renovation of Stage Control Systems
Complex stage control systems include many computer-based components with limited lifespans. These components often fail sooner than the mechanical or hydraulic parts of the stage machinery, and replacement parts become scarce over time.
It is therefore increasingly necessary to renew or modernize only the control system. Each case requires careful analysis to determine which components can be reused to remain cost-efficient. In some situations, an extended manufacturer upgrade can be more economical than a complete redesign — though public procurement regulations may complicate this option.
A thorough conceptual and technical assessment of the control system renewal at an early stage is therefore strongly recommended.
Simple Control Systems
Not all stage machinery requires complex, computer-based systems. For example, drives that are not used scenically during performances can often be operated with simple fixed control panels.
Such systems can still include useful comfort features:
- height position indicators for manual repositioning
- soft-start functions to prevent jerking that could disturb lighting or stage setups
These simpler systems can be practical, reliable, and cost-effective solutions when appropriately designed for their specific use case.