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world of industries 8/2016 (EN)

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world of industries 8/2016 (EN)

Machines should not pose

Machines should not pose risks A number of different standards and guidelines regulate the assessment of machine related hazards and how they should be dealt with by manufacturers and operators. SMC products can be used to support the objective of reducing risks and ensuring machine safety with a range of intelligent products. Machines should not pose any significant risks to people. Functions that are commonly used by machine builders to reduce risk in pneumatics are “Safe venting”, “safe stop”, “two-hand actuation” and “protection against unintentional start-up”. SMC has products which can be used to help fulfil these principles. About SMC The company SMC is a manufacturer of pneumatic and electrical automation technology and also a partner for individual solutions. The more than 12,000 product groups include air treatment, valves and throttles, actuators (pneumatic and electrical), screw fittings and hoses as well as vacuum and instrumentation components. Headquartered in Tokyo, SMC has a total of 400 sales offices in 82 countries and offers automation solutions on all five continents. In Europe, Machinery Directive 2006/42/EC in conjunction with EN ISO 13849 standard requires that, for example, pneumatic drives must be in a safe state when opening protective enclosures. As a second example, when manually removing parts from a conveyor belt, safety precautions must be taken to ensure that all the drives in the hazardous area are in a safe state. Often a light barrier will be used which issues a signal to the control system which is responsible for performing the stop and ensuring that no unintentional machine startup may occur within the danger area while personnel are present. Secured position The SMC solenoid valve series VQC2000-X27, VQC4000-X17 as well as the SY3000/5000/7000 series are compatible with the “secured position” safety principle. The valves satisfy the requirements of EN ISO 13849 for use in safety related control systems. Both series have a soft-sealing, bistable valve with detent option (VQC-X77 and SY-X25). Systems that rely purely on friction do not satisfy the requirements of the standard. Important practical considerations for ensuring safe application are that the pneumatic valves and the pressure switch is assembled close to the valve to detect the pressure in the circuit. For diagnostics SMC has a range of different pressure sensors and in addition a range of position switches to detect the cylinder piston position. Safe venting If the guard doors are opened while a system is in operation, or a person accesses a defined hazardous area in which, for example, a robot arm is in operation, the pneumatic system and the robot must be safely stopped. In this case venting of the pneumatic system is advisable. Furthermore, no unintentional machine or robot start-up may occur within the hazardous area during maintenance activities. SMC valves MDA INDIA 32 World of Industries 8/2016

MEASUREMENT AND CONTROL in the VP-X536, VP-X538, VP-X555 and VG342-X87 series can be used to provide protection when part of the safety related control system by venting the air. As safety components, they satisfy the requirements of Machinery Directive 2006/42/EC. An integrated limit switch achieves a diagnostic coverage of 99 %. This fulfils the requirements of EN ISO 13849. In addition the VR51 two-hand control valve is available for some cases where it is necessary to ensure the operator’s hands are clear from the hazardous area. It can be used in purely pneumatic control systems. Strong partner In Europe, a range of standards and regulations ensure a high level of safety for the workforce when using machinery. Machinery Directive 2006/42/EC requires a risk assessment in accordance with EN ISO 12100 to identify the risks that must be evaluated and mitigated. Harmonised standard EN ISO 13849 describes a probabilistic method for reducing the risks of control systems. It applies for mechanical, pneumatic, hydraulic and electrical control systems and has become an established method in mechanical engineering. EN ISO 13849- 1 describes general design principles and EN ISO 13849-2 defines the validation of the control system as well as the components. SMC meets this package of requirements with different products, which provide optimal support for machine manufacturers and operators in their efforts to ensure safe operation. Robot arm 01 The EX600 dual port fieldbus systems with QuickConnect function are perfect for applications with frequent tool changes. This minimises start-up and connection times to EtherNet/IP networks Photographs: SMC Pneumatik www.smc.eu 02 The VP-X555 venting valve series has a direct monitoring and soft-start function World of Industries 8/2016 33