Machine Safety
Every manufacturer must assess the risks posed by its products in accordance with the Machinery Directive 2006/42/EC (MD) to protect people who come into contact with the machinery. However, the Machinery Directive does not apply exclusively within Europe. It also applies in other countries within the European Single Market. Local standards often refer to the European safety standards listed in the MRL as harmonized standards.
The risk posed by the machine must be reduced to the point where the remaining residual risk is acceptable. To make this assessment, the manufacturer conducts a three-step risk assessment. The risk must be reduced through design, technical safeguards, and user information, such as manuals.
Quick read
Machine safety is a subfield of functional safety in mechanical engineering and serves to reduce risks to people to an acceptable residual risk through appropriate protective measures. Manufacturers assess risks in accordance with the Machinery Directive 2006/42/EC and derive appropriate safety functions from these assessments. The design of technical protective measures is based on Performance Levels (PL), which describe the probability of failure of safety-related components. TURCK supports machine safety with TBPN safety I/O modules for PROFIsafe and TBIP modules for CIP Safety, with the TBSB shut-off box, and with the SC10, SC26, and XS26 safety controllers from Banner Engineering. These solutions enable centralized and decentralized safety concepts based on Profinet, Modbus TCP, EtherNet/IP, PROFIsafe, CIP Safety, and ISD. Safety applications can be configured, simulated, and documented using graphical software.
Functional Safety for Machines and Processes
Every manufacturer must assess the risk posed by its products in accordance with the Machinery Directive 2006/42/EC (MD) to protect people who come into contact with the machine. However, the Machinery Directive does not apply exclusively within the EU. It also applies in other countries within the European Single Market. Local standards often refer to the European safety standards listed in the MD as harmonized standards.
The risk posed by the machine must be reduced to the point where the remaining residual risk is acceptable. To make this assessment, the manufacturer conducts a three-step risk assessment. The risk must be reduced through design, technical protective measures, and user information such as manuals.
Classifying Hazards by Performance Level
To assess which technical protective measures are appropriate for a given risk, manufacturers rely on metrics that indicate the probability of failure of safety-related components: the Performance Levels (PL). First, the manufacturer determines the target Performance Level (PLr) of a safety function. After designing a safety control system to implement this function, the manufacturer determines the actual Performance Level. At the end of the process, PL and PLr must match. Broadly speaking, three types of safety control systems can be distinguished.
Three Concepts of Machine Safety
1. Relay Technology
Traditional safety technology uses safety relays. The safety logic is implemented via hard-wired contacts. For example, the relays ensure that a drive cannot be started as long as a safety light curtain is still energized. These installations are relatively cost-effective and can be replicated worldwide.
No software is used in this process. However, in larger and more complex security installations, relay technology becomes difficult to manage. Troubleshooting and diagnostics for errors are very time-consuming. The system cannot perform a self-test.
2. Centralized safety wiring with safety controllers
Once a certain level of complexity is reached, it becomes more cost-effective to implement safety applications using safety controllers. Programs can be written in controllers or safety control systems that—to put it simply—link actions to conditions using Boolean operators (AND, OR, NOT, XOR).
Although the wiring for these applications is simpler than with relay technology, all safety signals must still be routed to the central controller in the control cabinet, which is both costly and time-consuming. The benefit of safety controllers is that safety programs can be copied and reused multiple times for similar machines. Expanding the safety functions is relatively straightforward. In addition, the safety applications can be displayed graphically via the HMI. Information and signals can thus flow from the controller to the PLC as well as from the PLC to the controller.
3. Decentralized Security Concepts
3.1: Decentralized wiring – centralized control
Safety signals can also be collected directly in the field via IP67 I/O modules and transmitted to a safety controller via a safety fieldbus or a secure Ethernet protocol. The control of the safety functions is then centralized, which—when factoring in bus cycle times and chained messages—may result in the need to account for longer response times. These, in turn, require greater distances between the protective devices and the sources of danger.
3.2 Decentralized wiring – decentralized control
Safety I/O modules from individual manufacturers can also control safety functions directly on the module in the field. With these consistently decentralized safety solutions, users can avoid potential problems caused by long cycle times. In addition, commissioning is made easier because individual machine parts or modules can be tested offline.
Both decentralized solutions offer efficient wiring using standard connectors. The information communicated to higher-level controllers simplifies the commissioning and diagnostics of the applications.
Benefits
Video: Safety Solutions – Functional Safety for People and Machines
Downloads and Products
Machine Safety in Practice: Added Value for Your Application
Efficient and robust solutions for real-world applications—designed for demanding operating conditions and proven in everyday industrial use.
Machine Safety at TURCK: Frequently Asked Questions
1. What is machine safety, and why is machine safety important for machine manufacturers?
Machine safety encompasses measures to reduce risks posed by machines. Machine safety is an integral part of the risk assessment required by the Machinery Directive 2006/42/EC and serves to protect people. Manufacturers identify risks, define safety functions, and compare the required performance level with the achieved performance level. TURCK supports various safety concepts with safety I/O modules and safety controllers.
2. Which machine safety concepts can be implemented using TURCK solutions?
Machine safety can be implemented using relay technology, centralized safety controllers, or decentralized safety concepts. TURCK offers solutions for decentralized architectures with the TBPN and TBIP safety I/O modules, as well as for centralized architectures with the SC10, SC26, and XS26 safety controllers. This allows users to implement safety functions centrally or decentrally, depending on the system structure.
3. Which TURCK products are suitable for decentralized machine safety?
For decentralized machine safety, TURCK offers the TBPN safety I/O modules for PROFIsafe and the TBIP modules for CIP Safety. The modules feature their own safety controller and allow safety functions to be pre-programmed and tested even before commissioning. During operation, a central safety controller can then control the application via Safety Ethernet.
4. Which protocols does TURCK support for machine safety and industrial networks?
Machine safety at TURCK is based on several safety and automation protocols. The TBPN safety I/O modules support PROFIsafe, while the TBIP modules are designed for CIP Safety. The SC10, SC26, and XS26 safety controllers can be used as devices or slaves in Profinet, Modbus TCP, or EtherNet/IP networks. This allows safety applications to be deployed in a variety of automation environments.
5. How is machine safety programmed using TURCK safety controllers?
Machine safety is implemented in Banner Engineering's safety controllers using graphical safety programs. The software supports the configuration and simulation of safety applications and offers documentation features. Safety functions are described using logical operators such as AND, OR, NOT, or XOR and are then transferred to the controllers.
6. What machine safety software does TURCK provide, and what features does it offer?
TURCK offers free software with a graphical user interface for its safety controllers. The software supports the configuration, simulation, and documentation of safety applications. Programs can be transferred to other controllers via USB sticks. This allows identical safety applications to be used on multiple machines.
7. How can safety functions be visualized in machine safety?
Machine safety can be displayed graphically using safety controllers via a Human-Machine Interface (HMI). Safety information and signals can be exchanged between the safety controller and the PLC. This makes the states and signals of the safety application available for visualization and diagnostic tasks.
8. How does TURCK support diagnostics and safety data in machine safety applications?
Machine safety benefits from additional diagnostic information provided by the components used. The SC10 safety controller supports the ISD protocol, which allows access to the switching states and diagnostic data from safety sensors. Decentralized safety concepts also transmit information to higher-level controllers, thereby supporting commissioning and diagnostics.
9. What cost and licensing considerations should be taken into account with TURCK solutions for machine safety?
Free software is available for the safety controllers to configure and simulate safety applications. The source code does not describe any additional licensing models or licensing costs. The source code indicates that passive safety concepts using TBSB shut-off boxes and decentralized I/O components can be designed as a relatively cost-effective safety solution.
10. In what practical applications are TURCK solutions used for machine safety?
Machine safety solutions from TURCK are used in a variety of applications, including modular machine designs, intralogistics, hydrogen infrastructure, and production facilities. Examples from the source text include the processing of safety signals on presses, decentralized muting of optical safety devices, collision protection on Mobile Equipment, and safety concepts for modular production environments.