Machinery Protection Devices - British Automation & Robot ...

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5.3.1 Emergency stop switchThe switch is the device that initiates the emergency stop. It mustsustain this signal until disengaged by the appropriate action.EN 418 is the consultative document for emergency stopping,explaining the differences between the design of a normal stop andan emergency stop. It defines the safety requirements of the deviceas “having the principle of positive actuation to achieve contactseparation that is not dependent on springs …Any action on theactuator which generates the signal for an emergency stop mustresult in a latching of that actuator. The resetting of the actuator shallbe only by a manual action”.32128The emergency stop switch actuator may take different forms,depending on the application in which it is being used, for example:Machinery ProtectionDevicesMushroom-headed buttonsBarsLeversKick-platesPressure-sensitive cables.The colour or the actuator must be red. Where used, the backgroundcolour must be yellow.5.3.2 Emergency stop circuitThe integrity of the circuit can be decided in conjunction with the riskassessment. EN 954-1 outlines the requirements for safety-relatedcontrols. In general, the stop circuit can be viewed along thefollowing lines.
E-StopFinal control elementFig. 35: Category B and 1 stop circuitThis is the type of circuit that meets the requirements of categories Band 1, in accordance with EN 954-1. The emergency stop pushbutton has positive actuation and will always break the circuit. Thecontrol relay is a spring-return device. As the failure mode is notclearly defined, this could lead to failure to closed circuit. However,the aim of these categories is to achieve good design using well-triedcomponents and, if a failure does occur, the risk to the operator orenvironment is low.33129Machinery ProtectionDevicesE-StopResetFig. 36: Category 2 stop circuit using a safety relayFinal control element
Page 1 and 2: Chapter 5Machinery Protection Devic
Page 3 and 4: 5.0 GuardsA guard is defined as par
Page 5 and 6: 4This will be determined by the ris
Page 7 and 8: PNOZ X6PST 26Fig. 10: Two-channel c
Page 9: lock. Keys are uniquely coded and c
Page 15 and 16: FORTRESSINTERLOCKSFORTRESSINTERLOCK
Page 17 and 18: 16Fig. 18:With the AMLOK normally c
Page 19 and 20: Calculate the safety distanceThe sa
Page 21 and 22: The following table shows the formu
Page 23 and 24: 1256 mm minimumx = d < H / 15 + 50
Page 25 and 26: 5.2.4 Connection to control circuit
Page 27 and 28: 5.2.4.1 Typical connection+ 24 VDC1
Page 29: LCU-P outputin ON stateAOPD outputA
Page 32 and 33: 5.2.6 Pressure-sensitive safety dev
Page 36 and 37: The next category of EN 954-1 makes
Page 38 and 39: Electromechanical and hydraulic cir
Page 40 and 41: E-StopY1Y2Y138134Machinery Protecti
Page 42 and 43: 5.3.4 Typical connectionsL1L2L34013
Page 44 and 45: L1L2L3F0Control CircuitFusesT1Contr
Page 46 and 47: E-StopPP24VMonitored dump valvesV1
Page 48 and 49: EN 574 (Safety of machinery. Two-ha
Page 50: 5.4.2 Programmable electronic syste

Machinery Protection Devices - British Automation & Robot ...

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