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Safety Relay
Safety relays are devices that generally implement safety functions. History Relays and contactors were used to control plant and machinery in the early days of control technology. In the event of a hazardous situation, the actuator was simply isolated from the energy supply. This type of protection system could be manipulated in the event of a malfunction, disabling the protective function. Special relay circuits, such as the three-contactor combination, were the first designs to come out of deliberations into how this could be avoided. These device combinations led to the development of the first safety relay from the German automation manufacturer Pilz (company), Pilz, the PNOZ. Description In the event of a hazard, the task of safety functions (e.g. Kill switch, E-STOP, safety gate or standstill monitoring) is to use appropriate measures to reduce the existing risk to an acceptable level. These many safety functions include: * Kill switch, Emergency stop pushbuttons * Safe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relays
A relay Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts An automotive-style miniature relay with the dust cover taken off A relay is an electrically operated switch. It consists of a set of input terminals for a single or multiple control signals, and a set of operating contact terminals. The switch may have any number of contacts in multiple contact forms, such as make contacts, break contacts, or combinations thereof. Relays are used where it is necessary to control a circuit by an independent low-power signal, or where several circuits must be controlled by one signal. Relays were first used in long-distance telegraph circuits as signal repeaters: they refresh the signal coming in from one circuit by transmitting it on another circuit. Relays were used extensively in telephone exchanges and early computers to perform logical operations. The traditional form of a relay uses an electromagnet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
