Single line control for HVAC actuator

• US 7,787,994 B2
• Filed: 09/05/2006
• Issued: 08/31/2010
• Est. Priority Date: 09/05/2006
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Wacker, Paul C.
• Primary Examiner(s): Rodriguez; Paul L
• Assistant Examiner(s): ORTIZ RODRIGUEZ, CARLOS R
• Application Number:
  US11/470,200
• Publication Number:
  US 20080058966A1
• Time in Patent Office: 1,456 Days
• Field of Search: 700/276, 318/618, 318/254.1, 318/255, 318/811, 62125-131, 621/57, 622/31, 388800-806, 388809-815
• US Class Current: 700/276
• CPC Class Codes: H02P 23/0077 Characterised by the use of a particular software algorithm

Abstract

Methods and systems for controlling an HVAC actuator using a single output control signal are disclosed. In one illustrative embodiment, the single output control signal may be a digital signal that serially encodes desired position data (either an absolute position or a relative position) for the HVAC actuator. In some cases, the single output control signal is provided by a controller remote from the HVAC actuator, and is received by the HVAC actuator. The HVAC actuator may include a controller for decoding the serially encoded data contained in the single output control signal, and for controlling the HVAC actuator accordingly.

Claims

1. 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.

2. The HVAC actuator of claim 1 wherein the motor is a DC brushless motor, and the controller is configured to control commutation of the motor.

3. A method for controlling an HVAC damper or valve having a motor and an actuated part for regulating the flow of a fluid through a conduit of an HVAC system, the method comprising the steps of:

encoding a serial bit stream that includes a sequence of two or more bits on a single output control signal by sequentially modulating a substantially sinusoidal AC waveform, such that the presence of a half-cycle of the substantially sinusoidal AC waveform for one of the two or more bits is interpreted as a bit having a first logical value, and the absence of a half-cycle of the substantially sinusoidal AC waveform for one of the two or more bits is interpreted as a bit having a second logical value, wherein the logic levels for the sequence of two or more bits of the serial bit stream encode a value that corresponds to an absolute position of the HVAC damper or valve to regulate the flow of the fluid through the conduit of the HVAC system;

sending the encoded serial bit stream to the HVAC damper or valve;

decoding the logic levels of the sequence of two or more bits of the serial bit stream to determine the value that corresponds to the absolute position of the HVAC damper or valve; and

providing one or more control signals to the motor to drive the actuated part to the absolute position.

4. The method of claim 3 wherein the decoding step is performed by a processor.

5. The method of claim 4 wherein the processor also controls commutation of the motor.

6. The method of claim 5 wherein the motor is a DC brushless motor.

7. The method of claim 3 wherein the encoding step includes selectively switching on and off a switch.

8. The method of claim 7 wherein the switch is a Triac, and a processor selectively switches the Triac on and off.

9. The method of claim 7 wherein the switch is a Triac, and a processor selectively switches the Triac on and off to encode the serial bit stream of two or more bits on the single output control signal.

10. The method of claim 9 wherein the switch is a Triac coupled to an AC signal, and the Triac passes the AC signal onto the single output control signal when the Triac is “

on”

, and blocks the AC signal from reaching the single output control signal when the Triac is “

off”

.

11. A system for controlling a position of an HVAC actuator using a single output control signal, the system comprising:

a HVAC controller for controlling the position of the HVAC actuator, the HVAC controller including;

an output port; and

a processor for causing a sequence of two or more bits of a serial bit stream to be impressed upon the single output control signal at the output port by modulating a substantially sinusoidal AC signal, such that the presence of the substantially sinusoidal AC signal is interpreted as a first logic value for a corresponding one of the two or more bits, and the absence of the substantially sinusoidal AC signal is interpreted as a second logic value for a corresponding one of the two or more bits, 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;

wherein the HVAC actuator includes;

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 coupled to the output port of the controller;

a second controller for receiving the serial bit stream that is impressed on the single output control signal at the input port; and

the second controller configured to decode the value from the logic levels of the sequence of two or more bits of the serial bit stream to determine 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.

12. A controller for controlling a position of a remotely located HVAC actuator comprising:

a HVAC controller for controlling the position of the HVAC actuator, the HVAC controller including;

an output port;

a processor for causing a serial bit stream having two or more bits to be impressed upon a single output control signal at the output port of the HVAC controller;

a switch, wherein the processor controls the switch such that the switch controls a sequence of two or more bits of the serial bit stream that is impressed upon the single output control signal at the output port, wherein the switch, when open, provides an AC signal on the single output control signal which is interpreted as a first logic level for a corresponding one of the two or more bits, and when closed, prevents the AC signal from reaching the single output control signal which is interpreted as a second logic level for a corresponding one of the two or more bits; and

wherein the logic levels of the sequence of two or more bits of the serial bit stream encode a value that corresponds to an absolute position of the HVAC actuator.

13. The controller of claim 12 wherein the HVAC actuator includes:

an actuated part;

a motor coupled to the actuated part, the motor configured to drive the actuated part to various positions;

an input port coupled to the output port of the HVAC controller;

a second controller for receiving the two or more bits of the serial bit stream that is impressed on the single output control signal at the input port; and

the second controller configured to decode the logic levels of the sequence of two or more bits of the serial bit stream to determine the absolute position of the HVAC actuator, and provide one or more control signals to the motor to drive the actuated part to the absolute position.

14. The controller of claim 13 wherein the switch is a Triac.

15. The controller of claim 13 wherein the motor is a DC brushless motor, and the second controller is configured to control commutation of the motor.

16. The controller of claim 12 wherein the switch, when open, provides a logic “

one”

for the corresponding one of the two or more bits on the single output control signal, and when closed, provides a logic “

zero”

for the corresponding one of the two or more bits on the single output control signal.

17. The controller of claim 12 wherein the switch, when open, provides a logic “

zero”

for the corresponding one of the two or more bits on the single output control signal, and when closed, provides a logic “

one”

for the corresponding one of the two or more bits on the single output control signal.