Patent ID: 7787994

Claim:
An HVAC actuator, comprising: an actuated part for regulating the flow of a fluid through a conduit of an HVAC system; a motor coupled to the actuated part, the motor configured to drive the actuated part to various positions; an input port; a controller for receiving a serial bit stream including a sequence of two or more bits that are sequentially impressed on an input control signal at the input port of the HVAC actuator, wherein each of the two or more bits have a corresponding logic level, wherein the controller interprets a first logic level for a corresponding one of the two or more bits when an AC signal is present on the input control signal at the input port, and interprets a second logic level for a corresponding one of the two or more bits when the AC signal is not present on the input control signal at the input port, and wherein the logic levels of the sequence of two or more bits of the serial bit stream encode a value that relates to a desired position of the HVAC actuator; and the controller is further configured to decode the logic levels of the sequence of two or more bits of the serial bit stream on the input control signal to determine the value that corresponds to the desired position of the HVAC actuator, and to provide one or more control signals to the motor to drive the actuated part to the desired position.