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The device is designed in such a way that any faults in the input circuit are detected, e.g. contact welding on an emergency off/emergency stop pushbutton or on one of the safety contacts on the output relay. The safety device stops the device switching back on and thereby stops the activation of relays K1 and K2. [1]
An output signal switching device (OSSD) is an electronic device used as part of the safety system of a machine. It provides a coded signal which, when interrupted due to a safety event, signals the machine to shut down. It works by converting the standard direct current supply, usually 24 volts, into two pulsed and out-of-phase signals.
Digital protective relays are primarily IEDs, using a microprocessor to perform several protective, control and similar functions. A typical IED can contain around 5–12 protection functions, 5–8 control functions controlling separate devices, an autoreclose function, self monitoring function, communication functions etc. [citation needed]
Speed: Devices must function quickly to reduce equipment damage and fault duration, with only very precise intentional time delays. Sensitivity: Devices must detect even the smallest value of faults and respond. Economy: Devices must provide maximum protection at minimum cost. Simplicity: Devices must minimize protection circuitry and equipment.
For example, this was the approach taken by OpenBSD in 2005 with its bio(4) pseudo-device driver and the bioctl utility, which provide volume status, and allow LED/alarm/hotspare control, as well as the sensors (including the drive sensor) for health monitoring; [7] this approach has subsequently been adopted and extended by NetBSD in 2007 as ...
Interrogation and remote operation capabilities allow utilities to aggregate data about their network performance, and develop automation schemes for power restoration. Automation schemes can either be distributed (executed at the remote recloser level) or centralized (close and open commands issued by a central utility control room to be ...
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Control engineers are responsible for the research, design, and development of control devices and systems, typically in manufacturing facilities and process plants. Control methods employ sensors to measure the output variable of the device and provide feedback to the controller so that it can make corrections toward desired performance.