Abstract

An electrically-powered zone condition control apparatus includes a first multiplexing means adapted for receiving analog status signals emanating from a plurality of passive signaling devices such as temperature or humidity sensors or potentiometers and transmitting these status signals in multiplex fashion to an analog-to-digital converter. The converter changes these analog status signals to digital data signals and directs them to a microcomputer. A second multiplexing means receives binary input signals which may indicate, for example, that an electrical contact is open or closed and also transmits these signals in multiplex fashion to the microcomputer. The microcomputer is adapted to perform algorithmic decisional functions relative to the signals received therein and is adaptable to periodically, selectively transmit digital output signals to one or more of a plurality of digitally-addressable load devices coupled to it by a two-wire communication bus. The microcomputer is also adaptable to periodically receive digital input signals from one or more of the load devices.A method for controlling a condition in a zone, temperature for example, includes the steps of generating a plurality of signals representative of the status of a plurality of signalling devices, converting selected status signals to digital data signals and directing the data signals and unconverted status signals to a computing means such as a microcomputer. The microcomputer performs algorithmic decisional functions relative to the signals received thereat and periodically, selectively transmits digital output signals along a communication bus to one or more of a plurality of uniquely, digitally addressable load devices. Digital input signals are periodically received from one or more of the load devices.