Pneumatic safety

Safe pneumatic drive technology for the required outcome

In practice, the topic of safety relating to pneumatic components should always be considered, with technical documentation and risk assessments determining its importance. The EC Machinery Directive 2006/42/EC is the definitive fundamental guideline for the functional safety of machines, and the harmonised standard EN ISO 13849 is also relevant. The good news is that Festo can provide expert support on all safety-related topics. As well as advice, we also offer precise application notes for our solutions.

Pneumatics with safety service

Festo offers a wide range of individual pneumatic components that need to be assessed as part of the system. It is not like electrics where you work with certified components; instead, the functional safety of a specific pneumatic application usually needs to be designed and built with common hardware components. In this case, it is the machine manufacturer's responsibility to provide the safety-related evaluation and documentation.

Safety-related pneumatics is anything but trivial, which is why we provide our products with all the relevant data as standard. What’s more, our project engineers are on hand to offer you expert advice until you are up to date with what is required, for example by going through the Failure Mode and Effects Analysis with you. This service provides you with a quicker and more cost-effective way to ensure your system is safe.

Active safety sub-functions that affect systems

SDE: safe de-energisation

The SDE function enables the downstream pneumatic system to be safely disconnected and de-energised.

Application note:

Safe de-energisation with soft start/quick exhaust valve MS6-SV-...-E (PDF)

SEZ: safe energisation

The SEZ function permits safe energisation using a defined force/time function (soft-start function).

SBC: safe brake control

The SBC function provides a safe output signal for controlling an external brake or clamping unit.

Active safety sub-functions that affect drives

STO: safe torque off

The power supply to the pneumatic drive is disconnected. The chambers of the pneumatic drive are exhausted so that no force (torque) can be generated that could lead to a dangerous movement.

Application notes:

SSB – safe stopping and blocking

The pneumatic drive is brought to a standstill. The free movement of the output component is blocked. It can be blocked by positive locking or friction locking.

SB – safe blocking (not part of VDMA 24584)

The free movement of the output component is blocked. It can be blocked by positive locking or friction locking.

Application note:

Definitions of pneumatic safety sub-functions: SB-f, PUS

SSC – safe stopping and closing

The supply of energy to or dissipation of energy from at least one chamber of the pneumatic drive is closed, and the energy that has thus been saved can be used for the shutdown.

Application note:

Definitions of pneumatic safety sub-functions: SSC, PUS

SET – safe equilibrium of torque

The SET function prevents the pneumatic drive from deviating from the torque (force) equilibrium by more than a specified value.

PUS – prevention of unexpected start-up; lockout-tagout

The PUS function prevents the start position of the valve from changing and leading to an unexpected start-up of a machine function.

SLS – safely limited speed

The SLS function prevents the pneumatic drive from exceeding the permissible speed.

SLT – safely limited torque (force)

The SLT function prevents the pneumatic drive from exceeding the permissible torque (force).

SDI – safe direction

The SDI function prevents the drive from moving in the incorrect direction.

Application note:

Definitions of pneumatic safety sub-functions: SDI, PUS

SOS – safe operating stop

The SOS function prevents the drive from deviating from the stopping position by more than a specific amount. The compressed air supply is maintained to enable the drive to withstand the effect of external forces (e.g. variable load) without further measures (e.g. mechanical holding brakes).

THC – two-hand control

Two-handed and simultaneous actuation of two control elements activates an output signal.

SS1 – safe stop 1

The volumetric flow rates into and out of the two chambers of the pneumatic drive are reduced or blocked. This slows down the movement of the drive and brings it to a stop. If the standstill is reached in accordance with the specified tolerance window, the pressure in the chambers of the pneumatic drive is reduced so that no force (torque) is generated that could lead to a dangerous movement.

SS2 – safe stop 2

The volumetric flow rates into and out of the two chambers of the pneumatic drive are reduced or blocked, thus slowing down the movement of the drive and bringing it to a stop. If the standstill is reached in accordance with the specified tolerance window, the pressure in the chambers of the pneumatic drive is maintained so that the existing pressure can be used to maintain the standstill.

We help you to achieve a safe machine in factory automation and a safe system in the process industry.

How? Take a look at our guidelines for machine and system safety. Here you’ll find not only comprehensive information about the fundamental standards, risk assessment and risk reduction, but also detailed overviews of all safety functions with the right products to integrate these functions in your system.

The guidelines also include an overview of all the seminars offered by Festo Training and Consulting for safety engineering qualifications.

Interested?

Find out more in the guidelines for machine and system safety (PDF)