Improvements relating to emergency lighting units and installations

摘要

An emergency lighting unit with a receiver for receiving signals transmitted through space is disclosed. The unit has a light and a battery with charging circuitry for powering the light in the event of a mains failure. Control circuitry is provided which is capable of being switched between at least a first condition wherein the light is powered from a mains electricity supply, and a second condition wherein the light is powered by the internal battery. The lighting unit is also provided with a transmitter, a memory bank and monitoring circuitry such that when the lighting unit is caused to enter a test mode in which it is powered by the battery, various operating characteristics such as battery voltage, light output intensity, estimated remaining battery charge and time to depletion can be measured, and either stored in the memory bank or immediately transmitted to a hand-held transmitter/receiver device which can display the relevant information to a user. Alternatively, the user may arrive in the vicinity of the lighting unit well after the test mode has finished, and simply request the unit to transmit all the operating information stored in its memory bank. The transmission of information from the lighting unit is effected through space.