A new system for the digital setting of temperature and humidity controllers

A system for programmed setting of electronic temperature or humidity controllers, which can commandany of sixteen available settings, is described. The main application is to a set of controlled climate rooms which have different levels of temperature and humidity by day and by night. A defined change from one level to another is required.Wheatstone bridges, set to give the required day and night conditions, are adjusted by transistor switches operated in binary sequence from the states of a counter. These give sixteen steps between and including the day and night settings. The selection of these steps in time is done by a train ofpulses whose rate defines a period for the change between day and night levels. By operation of two switches, the counter is commanded to `increase¿, `decrease¿, or `stop¿. The system can be used for programs more complex than a defined change.