GB2005872A - Improved thermostat - Google Patents

Abstract

A wall mounted thermostat is arranged to accept and convert manually generated instructions to binary encoded electronic impulses to control ambient air conditions. A building heating control reduces the desired ambient temperature at night, beginning at a prescribed time and returning to a higher daytime level at a different prescribed time. The system may also adjust desired temperature depending upon humidity conditions and alter the timing of heating and air conditioning control by predicting when a desired temperature will be reached in order to avoid overshoot. The system includes a liquid crystal or light emitting diode display (12) and communicates with a power source (78) and with heating and air conditioning switches (85,87) such as relays or contactors. In an accumulator unit (34), an analog to digital converter converts actual temperature signals (104) into binary form. A memory (36) stores a manually-entered desired temperature, and the accumulator functions as a comparator of the actual temperature binary signal with the stored desired temperature binary signal to provide a heating or cooling actuating signal (70). A buffer (65,67) is interposed between the A-D converter and the comparator to form an average of successively received actual temperature signals so as suppress response to misleading transitory excursions of sensed temperature. <IMAGE>