In the manufacturing sector, anywhere that humans mix with machinery is a potential danger zone. Even in the modern production line, people are often still an essential element of the production or packaging process, but moving conveyor belts, robotic arms, chopping blades and other moving machinery nearby can cause serious injuries or even loss of life.
The European Machinery Directive is heavily focused on safety, and one of its key targets is to lower the number of accidents in the industrial workplace. In areas where close cooperation between humans and machines are required, life and health must always take first priority, and risks must be minimised. Machinery and systems therefore need to be designed to leave no room for mistakes or defects which may cause hazards to humans.
Many European countries have built their reputations on the production of safe, reliable and sophisticated industrial machinery and systems, and these machines are almost always designed, installed and maintained with elements of functional safety in mind. Even so, there are still many pieces of machinery that do not put the interests of the user at the forefront of the design process. These machines are often impractical and hinder the operators in the execution of their work, which can often increase the safety risks, particularly if the operator bypasses or avoids essential safety functions.
Broadly speaking, it is the automatic safety function that either ensures that the intended function is performed correctly or where this is not possible, ensures that the system will shut down in an orderly, and therefore safe, way. Functional safety is governed by two main industry standards addressing the safety lifecycle and the different types of failures from faults: IEC61508 and IEC61511.
For machine designers, it’s clear that following the Machinery Directive is not just about simply buying components that offer safety certification. Comprehensive hazard and risk assessments must first be carried out to ensure not just the operator’s safety but also ease of use. Once the design process is complete, technical safety measures can be implemented, such as placing guards around the machine and selecting components that offer excellent functional safety features.
Process shutdown in motion control machineries such as servo motors and drives are becoming increasingly important, particularly for critical elements such as brakes on vertical axes. Ensuring that the stopping reaction time is fast enough to protect body parts from the force of the motion is essential, and this needs to be tested very regularly.
Shutdown systems must be additionally responsive and flexible in applications such as packaging and production machinery which require a high extent of machine safety. Functional safety components can be connected via safety input-output (I/O) or other proprietary bus systems, but the most advanced solutions are based on safety fieldbuses which are flexible and powerful.
Parker now offers an advanced PSD line of products with Functional Safety over EtherCAT (FSoE), providing a complete, centralised functional safety solution that requires no additional wiring.
A powerful, freely-programmable FSoE master, the Parker Safety PLC, addresses all safety components via the network such as safety inputs and outputs as well as PSD drive controllers with integrated safety technology. External components such as light curtains, emergency buttons, and safety shut-off mats are connected through the safe I/O-Modules.
When functional safety is done correctly, the operator is not constrained in any way and should have no reason to avoid any safety devices. Similarly, machine uptime will not be negatively impacted due to safety techniques, ensuring smooth and efficient operations on the processing line.
Overall, the benefits of using servo drives with integrated safety functionality are hard to ignore; such as a reduction in wiring and components, ease of use, and increased productivity. Functional safety also has much to offer Industry 4.0. Not only is safety going to become increasingly important in automated factories where there will need to be a greater level of trust between machines and humans, but safety systems will also improve diagnostics, efficiency, and reliability.
To discover all the safety features offered by the PSD drive watch the animation.
This article contributed by Patrick Knebel, product manager - servo drives & controllers, Electromechanical and Drives Division Europe, Parker Hannifin Corporation