Abstract: An actuator for an HVAC system includes a motor coupled by a gear train to an output connector. A spring coupled to the gear train stores energy when the motor is driven in one direction and releases stored energy when the motor is driven in the opposite direction. The spring returns the output connector to a normal position in the event that electrical power is lost. A motor stall current threshold for the motor is determined dynamically in response to operation of the actuator. The position of the spring, direction of motion and the temperature are sensed. The motor stall current threshold value is selected from a table in response to the values of the sensed operating parameters. A determination is made that the motor has stalled when the electric current applied to the motor exceeds the selected motor stall current threshold value.

Abstract: An actuator for an HVAC system includes a motor coupled by a gear train to an output connector. A spring coupled to the gear train stores energy when the motor is driven in one direction and releases stored energy when the motor is driven in the opposite direction. The spring returns the output connector to a normal position in the event that electrical power is lost. A motor stall current threshold for the motor is determined dynamically in response to operation of the actuator. The position of the spring, direction of motion and the temperature are sensed. The motor stall current threshold value is selected from a table in response to the values of the sensed operating parameters. A determination is made that the motor has stalled when the electric current applied to the motor exceeds the selected motor stall current threshold value.

Abstract: An electric actuator return-to-normal failsafe system that utilizes a bank of storage capacitors to store electrical energy for returning an electrical actuator to a safe position in the event of a power failure. The failsafe system includes a regulator circuit that regulates the output of the storage capacitor such that a constant power output is applied to the electric actuator. The constant power output from the regulator circuit is also available to provide directional control of the actuator.

Abstract: A control system for controlling a climate control device, such as an HVAC device within a premise, utilizes real time price tier data supplied by the utility company to achieve economical temperature regulation of the premise. The control system regulates temperature based on time of day data and desired temperature data supplied by the user wherein the user may program different desired temperatures depending upon the relative cost of electricity. The system also provides billing information to the user for current usage and projected usage. The control system additionally controls appliance modules and regulates operation of the hot water heater.

Abstract: A low level, microprocessor based direct digital system controller includes power supply means for providing a source of regulated electrical power to the controller. A field programmable processor means transfers selected data base information to and receives status signals from a field interface means, digitally executes control and energy management algorithms respecting those signals in accordance with computer program routines selected from a library of mnemonically identified routines residing in the read only memory (ROM) portion of the processor means. The processor means responsively directs programmed data and digital command signals to the field interface means which periodically updates the data base of the processor means, analyzes and conditions signals received therein from the processor means and from remote data points and selectively controls the data points.

Abstract: A loop communication system includes a loop controller originating and terminating parallel output multiple bit message frames over a pair of trunks to remote stations, each of which includes a multiplexing connection means to the incoming trunk segments, with means to selectively and operably connect one of the incoming trunk segments to a frame processor. A pair of transmitters are also provided at the interface means and actuated to synchronously and correspondingly retransmit the process signal over the two outgoing trunk lines or segments. A logic circuit directly transmits the signal from one receiver and blocks the other until the first fails. The message is processed and retransmitted by a pair of transmitters over the two outgoing trunk segments. Suitable indicators coupled into the logic circuit signal the failure. A contact status circuit initiates transmission of the failure location via message frames to the controller.