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Occupancy sensor types include: PIR sensors, which work on heat difference detection, measuring infrared radiation.Inside the device is a pyroelectric sensor which can detect the sudden presence of objects (such as humans) who radiate a temperature different from the temperature of the background, such as the room temperature of a wall.
PIR sensors are commonly used in security alarms and automatic lighting applications. PIR sensors detect general movement, but do not give information on who or what moved. For that purpose, an imaging IR sensor is required. PIR sensors are commonly called simply "PIR", or sometimes "PID", for "passive infrared detector".
PIR sensors identify abrupt changes in temperature at a given point. As an intruder walks in front of the sensor, the temperature at that point will rise from room temperature to body temperature and then back again. This quick change triggers the detection. PIR sensors designed to be wall- or ceiling-mounted come in various fields of view ...
The personal needs allowance is the time that is associated with workers’ daily personal needs which include going to the restroom, phone calls, going to the water fountain, and similar interruptions of a personal nature. However, it is categorized as 5%, but it also depends on the work environment, e.g. in terms of discomfort and temperature.
Position vectors r and r′ used in the calculation. Retarded time t r or t′ is calculated with a "speed-distance-time" calculation for EM fields.. If the EM field is radiated at position vector r′ (within the source charge distribution), and an observer at position r measures the EM field at time t, the time delay for the field to travel from the charge distribution to the observer is |r ...
For long delay multipath, the receiver itself can recognize the wayward signal and discard it. To address shorter delay multipath from the signal reflecting off the ground, specialized antennas (e.g., a choke ring antenna) may be used to reduce the signal power as received by the antenna. Short delay reflections are harder to filter out because ...
In telecommunications, attack-time delay is the time needed for a receiver or transmitter to respond to an incoming signal.. For a receiver, the attack-time delay is defined as the time interval from the instant a step radio-frequency signal, at a level equal to the receiver's threshold of sensitivity, is applied to the receiver input, to the instant when the receiver's output amplitude ...
Modern time delay combination locks can have many functions such as multiple different codes, pre-set time lock settings (open and close times), pre-set vacation times (e.g. Christmas Day), dual code facility, and a full audit trail providing a detailed record of the lock history showing who opened the lock, when and how long it was open.