Page 63 of Current Catalog by Moeller Electric USA

02/022 esr electronic safety relays description fields of application safety category industrial control relays electronic timing relays electronic safety relays are used for monitoring safety control circuits the requirements for electrical equipment of machines are defined in accordance with iec/en 60 204 the machine user must assess the risk at his machine in accordance with en 954-1 and fit a control system which meets the requirements for the relevant safety category 1 2 3 or 4 esr electronic safety relays are approved by the german trade associations and comply with safety category 3 or 4 the safety category of a control system results from its combination with the external wiring for which the machine user is responsible the electronic safety relays are tolerant of one fault in other words a single fault in the safety circuit does not result in a dangerous state two mutually independent simultaneously occurring faults are excluded in en 954-1 construction stop category the electronic safety relay consists of a power section the electronics and two redundant relays with interlocked opposing contacts for the enabling and signalling paths iec/en 60 204-1 stipulates two relevant stop categories for stopping in the event of an emergency · stop category 0 stopping by means of immediate disconnection of power from the machine drive elements · stop category 1 controlled stopping where the power to the machine drive elements is retained in order to achieve cessation of machine movement the power is only interrupted when the machine has come to a standstill the safety relays for emergency-stop applications and non-delayed expansion modules are suitable for stop category 0 delayed contact expansion modules meet the requirements of stop category 1 product range overview the range includes relays for emergency-stop circuits function monitoring of safety mats and safety bumpers in fault-free operation following the starting command the safety circuits are monitored by the electronics and with the assistance of the relays enable the enabling paths following the switch off command and also in the event of a fault earth fault faulty insulation wire breakage etc the enabling paths are blocked immediately stop category 0 or with a time delay stop category 1 and the motor is disconnected from the mains supply in redundant safety circuits a short-circuit does not result in danger so only when the circuit is re-energized is the fault detected and starting prevented single/dual channel design monitoring of protective guards monitoring of two-hand controls safety relays for stopping in the event of an emergency and for monitoring of protective guards are available for single and dual channel applications the single channel construction enables earth-fault monitoring of the safety circuit for the dual channel application the emergency-stop circuit or the protective guard circuit is constructed as a redundant circuit in this way monitoring for short-circuits and wire insulation faults is also implemented furthermore the device can be used with or without reset monitoring the device is started only as a result of the falling edge of the on button and the enabling paths switched through an application for the device without restart monitoring is for example for monitoring protective doors for an automatic restart contact expansion modules with and without time delay are also available.

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