Abstract: A programmable thermostat has two way communication with a utility using a power carrier line signal across distributed low voltage power lines in a building downstream of an HVAC system transformer. The two way PLC communication includes transmission to the utility of response information regarding the response taken by the thermostat to a power “shed” command, and preferably also includes sensed temperature and/or temperature set point information. The HVAC system transformer includes an integral capacitive bypass path for PLC data transmission across the windings of the transformer. The thermostat positions its temperature sensor to avoid heat given off by the PLC receiver/transmitter and its electrical circuits as well as the thermostat microprocessor and the electrical power circuits therefore.

Abstract: A system for controlling a plurality of loads based upon command and residual priorities having a plurality of loads, a controller for controlling the loads according to at least two programs, each program having a command priority used for a program which wants control of a load and a residual priority retained for the program having control, the controller comparing the command priority of the program wanting control of the load to the residual priority of the program having control for thereby providing a command instruction to the load if the command priority of the program wanting control is greater than or equal to the residual priority of the program having control, and a communication channel connected between the controller and the loads for communicating the command instruction to the load.

Abstract: A protocol system for data processing equipment, particularly equipment used in building automation monitoring and control systems for air-conditioning control and monitoring of fire and security points is disclosed having a plurality of stations connected to a data bus, each station having an apparatus for monitoring the traffic on the data bus, calculating its turn to transmit or time slot during which it is permitted to transmit data on the bus and updating its calculated turn or time slot after each station designated to transmit in a turn or time slot after each station designated to transmit in a turn before it has transmitted data. Although each station has a designated time slot during which it may transmit, each time slot is of variable duration depending upon the extent of data to be transmitted.

Abstract: A system for cycling loads in a building is disclosed having a temperature sensor for sensing a temperature, a processing or computer apparatus for utilizing the sensed temperature to cycle the loads in the building on and off and a memory having a first portion for storing a schedule which contains information relating to the time sequence of the operation for the loads within the building and a second portion for storing a table which contains information related to the operational characteristics of each load covered by the table.