System for control of lights and motors

• US 20080278297A1
• Filed: 06/06/2006
• Published: 11/13/2008
• Est. Priority Date: 06/06/2005
• Status: Active Grant

• Current Assignee: Lutron Technology Company LLC
• Original Assignee: Lutron Electronics Company Incorporated (Lutron Electronics)
• Inventors: Blair, Edward J., Steiner, James P., Dobbins, Aaron
• Granted Patent: US 8,068,014 B2
• Time in Patent Office: Days
• US Class Current: 340/310.17
• CPC Class Codes: H04B 2203/5412 by modofying wave form of the power source
• CPC Class Codes: H04B 2203/5416 by adding signals to the wave form of the power source
• CPC Class Codes: H04B 2203/5458 Monitor sensor; Alarm systems
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines
• CPC Class Codes: H04L 1/0054 Maximum-likelihood or sequential decoding, e.g. Viterbi, Fano, ZJ algorithms
• CPC Class Codes: H04L 1/0072 Error control for data other than payload data, e.g. control data
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04L 25/0266 Arrangements for providing Galvanic isolation, e.g. by means of magnetic or capacitive coupling
• CPC Class Codes: H04L 25/0282 Provision for current-mode coupling

Abstract

A system for independent control of electric motors and electric lights includes a plurality of two-wire wallstations coupled in series via power wires between an alternating-current (AC) source and a light/motor control unit. The light/motor control unit is preferably located in the same enclosure as an electric motor and an electric light and has two outputs for independent control of the motor and the light. The light/motor control unit and the wallstations each include a controller and a communication circuit that is coupled to the power wiring via a communication transformer and communicate with each other using a loop current carrier technique. The light/motor control unit and the wallstations utilize pseudo random orthogonal codes and a median filter in the communication process.

Claims

1. A system for communicating between a first control circuit portion and a remote second control circuit portion over an electrical power wiring of a building, the first control circuit portion having a user actuable control for remotely controlling an electrical load controlled by the second control circuit portion, the system comprising:

a transmitter in the first circuit portion for transmitting control information over the power wiring to the second circuit portion;

a receiver in the second circuit portion for receiving the control information transmitted over the power wiring by the first circuit portion for controlling the load; and

further wherein

the first and second circuit portions each include a current responsive element coupled to the building power wiring for establishing a current signal loop in the building power wiring between the first and second control circuit portions for the exchange of the control information, and further wherein the electrical load comprises an electric motor.

2. The system of claim 1, wherein said current responsive elements each comprise a current transformer having a winding coupled to the building power wiring for establishing a current signal loop in the building power wiring between the first and second circuit portions for the exchange of the control information.

3. The system of claim 2, wherein said transmitter provides a modulated carrier signal onto said signal loop, wherein the carrier signal is modulated with said control information.

4. The system of claim 3, wherein said receiver receives said modulated carrier signal, demodulates the carrier signal and produces a detected signal containing said control information.

5. The system of claim 4, wherein the transmitter comprises a code generator for generating said control information in an encoded form and a modulator for modulating said encoded control information onto the carrier signal.

6. The system of claim 5, wherein the code generator comprises a pseudo random orthogonal code generator.

7. The system of claim 6, wherein the encoded control information comprises a first portion for providing synchronizing data for synchronizing a decoding operation, a second portion comprising a synchronization code and a third portion comprising message information for controlling said motor.

8. The system of claim 7, wherein the receiver comprises a median filter for removing impulsive noise signals from said modulated carrier signal.

9. The system of claim 6, wherein the code generator comprises a forward error correcting code generator.

10. The system of claim 1, wherein the electrical load further comprises an electric light and the electric light and electric motor are capable of being independently controlled by the control information.

11. A method for communicating between a first control circuit portion having a first current responsive element and a remote second control circuit portion having a second current responsive element over electrical power wiring of a building to control the operation of an electrical load including an electric motor, the first control circuit portion having a user actuable control for remotely controlling the electric motor controlled by the second control circuit portion, the method comprising the steps of:

coupling the first current responsive element to the electrical power wiring;

coupling the second current responsive element to the electrical power wiring;

establishing a current signal loop in the electrical power wiring between the first and second current responsive elements;

transmitting control information over the electrical power wiring from the first control circuit portion to the second control circuit portion; and

receiving the control information at the second circuit portion for controlling the motor.

12. The method of claim 11, wherein said step of establishing a current signal loop in the building power wiring comprises the steps of:

providing first and second current transformers at the first and second current responsive elements, respectively, each of the first and second current transformers having a winding; and

coupling the windings of the first and second current transformers to the electrical power wiring.

13. The method of claim 12, wherein said step of transmitting comprises the steps of:

modulating a carrier signal with the control information; and

coupling the modulated carrier signal onto the signal loop.

14. The method of claim 13, wherein said step of receiving comprises the steps of:

demodulating the modulated carrier signal; and

producing a detected signal containing the control information.

15. The method of claim 12, wherein the step of transmitting comprises the steps of:

encoding the control information;

modulating a carrier signal with the encoded control information; and

coupling the modulated carrier signal onto the signal loop.

16. The method of claim 15, wherein the step of encoding comprises the step of:

encoding the control information with a pseudo random orthogonal code.

17. The method of claim 16, wherein the step of encoding comprises the steps of:

encoding the control information such that the control information has a first portion for providing synchronizing data for synchronizing a decoding operation, a second portion comprising a synchronization code and a third portion comprising message information for controlling the motor.

18. The method of claim 17, wherein the step of receiving comprises the step of:

median filtering the modulated carrier signal at the second control circuit portion to remove impulsive noise signals from said modulated carrier signal.

19. The method of claim 15, wherein the step of encoding comprises encoding the control information as a forward error correction code

20. The method of claim 12, further wherein the electrical load further includes an electric light, the method further comprising the step of:

controlling the electric motor and the electric light with the control information independently of each other.

21. A load control system for controlling the power delivered to an electrical load from an AC voltage source, the system comprising:

a load control device coupled to the electrical load for control of the load, the load control device comprising a first current responsive element operatively coupled in series electrical connection between the AC source and the electrical load and a first communication circuit coupled to the first current responsive element for receiving message signals; and

a two-wire remote control device comprising a second current responsive element operatively coupled in series electrical connection between the AC source and the electrical load and a second communication circuit coupled to the second current responsive element for transmitting the message signals, the second current responsive element in series electrical connection with the first current responsive element; and

wherein the first current responsive element and the second current responsive element are operable to conduct a communication loop current the first communication circuit operable to transmit and the second communication circuit operable to receive the message signals via the communication loop current.

22. The system of claim 21, wherein the first communication circuit of the load control device and the second communication circuit of the two-wire remote control device are operable to both transmit and receive the message signals via the communication loop current.

23. The system of claim 22, wherein the first current responsive element comprises a first current transformer having a primary winding coupled in series electrical connection between the AC source and the electrical load and a second winding coupled to the first communication circuit, and

the second current responsive element comprises a second current transformer having a primary winding coupled in series electrical connection between the AC source and the electrical load and a second winding coupled to the second communication circuit.

24. The system of claim 23, wherein the first and second communication circuits each comprise a code generator operable to use Manchester encoding to generate an encoded signal from the message signal and a modulator operable to modulate the communication current loop with the encoded signal to produce a modulated signal.

25. The system of claim 24, wherein the first and second communication circuits each comprise a demodulator operable to demodulate the modulated signal to produce a detected encoded signal, and a median filter operable to remove impulsive noise signals from the detected encoded signal.

26. The system of claim 22, wherein the load control device is coupled to a plurality of electrical loads and is operable to individually control each of the plurality of electrical loads.

28. The system of claim 22, wherein the electrical load and the AC voltage source are coupled together at a common neutral connection and the load control device is coupled to the common neutral connection.

29. The system of claim 28, wherein the load control device comprises a capacitor coupled between the first current responsive element and the common neutral connection such that the communication loop current does not flow through the electrical load.

30. The system of claim 22, wherein the remote control device comprises a plurality of status indicators operable to provide an indication of the status of the electrical load.

31. The system of claim 30, wherein the first and second communication circuits are adapted to transmit and receive status signals.

32. The system of claim 22, wherein the remote control device and the load control device are operable to transmit the message signals using a system address;

and

wherein the remote control device and the load control device are operable to receive the system address in response to applying power to the remote control device and the load control device, respectively.

33. The system of claim 32, wherein the remote control device comprises an airgap switch such that power is removed from the remote control device and the load control device when the airgap switch is open and power is applied to the remote control device and the load control device when the airgap switch is closed.

34. The system of claim 22, further comprising a plurality of two-wire remote control devices, each comprising a respective current responsive element operatively coupled in series electrical connection between the AC source and the electrical load and a respective communication circuit coupled to the respective current responsive element for transmitting and receiving the message signals.

35. The system of claim 22, further comprising:

a plurality of two-wire remote control devices, each comprising a current responsive element operatively coupled in series electrical connection between the AC source and the electrical load and a communication circuit coupled to the current responsive element for transmitting the message signals.

36. The system of claim 22, further comprising:

a plurality of load control devices, each coupled to the electrical load for control of the load, each of the load control devices comprising a current responsive element operatively coupled in series electrical connection between the AC source and the electrical load and a communication circuit coupled to the current responsive element for receiving message signals.

39. The method of claim 32, further comprising the step of:

independently controlling each of the plurality of loads in response to the digital message.

27. The system of claim 27, wherein the plurality of electrical loads comprises an electric motor and an electric light.

37. A two-wire load control system for control of the power delivered to a plurality of electrical loads from an AC voltage source, the plurality of loads and the AC voltage source coupled together at a common neutral connection, the system comprising:

a load control device coupled to the plurality of loads and operable to individually control each of the plurality of loads;

the load control device comprising a first current responsive element coupled in series electrical connection between the AC source and the plurality of loads and a first communication circuit coupled to the first current responsive element for receipt of a message signal for controlling the plurality of loads;

a two-wire remote control device comprising a second current responsive element coupled in series electrical connection between the AC source and the plurality of loads and a second communication circuit coupled to the second current responsive element for transmission of the message signal for controlling the plurality of loads;

a capacitor coupled in shunt electrical connection with the plurality of loads;

wherein the capacitor, the AC source, the first current responsive element, and the second current responsive element are operable to conduct a communication loop current, the second communication circuit operable to transmit communication signals to the first communication circuit via the communication loop current.

38. A method for communicating a digital message from a two-wire remote control device to a load control device for independently controlling the power delivered to a plurality of loads from an AC voltage source, the method comprising the steps of:

coupling the two-wire remote control device in series electrical connection between the AC source and the load control device;

coupling a capacitor in shunt electrical connection across the plurality of loads;

conducting a communication loop current through the AC source, the two-wire remote control device, the load control device, and the capacitor, the loop current having; and

transmitting the digital message from the two-wire remote control device to the load control device via the current loop.

40. A method for assigning a system address to a first control device in a load control system for controlling the amount of power delivered to an electrical load from an AC voltage source, the method comprising the steps of:

coupling the first control device in series electrical connection between the electrical load and the AC voltage source via a power wiring, such that a load current is operable to flow on the power wiring from the AC voltage source to the electrical load through the first control device;

coupling a second control device in series electrical connection between the electrical load and the AC voltage source via a power wiring, the second load control device in series with the first control device such that a load current is operable to flow on the power wiring from the AC voltage source to the electrical load through the second control device;

applying power to the first and second control devices;

subsequently transmitting an address initiation request via the power wiring; and

receiving the system address via the power wiring.

41. The method of claim 40, further comprising the steps of:

choosing a random address to be the system address;

subsequently storing the random address as the system address in a memory; and

transmitting the system address via the power wiring.

42. The method of claim 41, further comprising the steps of:

transmitting a query message via the power wiring using the random address; and

determining whether a second control device responds to the query message.

43. The method of claim 40, further comprising the step of:

storing the system address in a memory in response to the step of receiving the system address.

44. The method of claim 40, further comprising the steps of:

determining whether the control device has the system address stored in a memory; and

subsequently transmitting the system address via the power wiring.

45. The method of claim 40, further comprising the step of:

entering an addressing mode in response to the step of applying power to the control device.

46. The method of claim 45, further comprising the step of:

exiting the addressing mode after a predetermined time after the step of entering the addressing mode.

47. A method of communicating a message signal from a first control device to a second control device, the message signal comprising a sequence of samples, the method comprising the steps of:

transmitting the message signal from the first control device;

receiving the message signal at the second control device;

examining a set of N sequential samples of the received message signal;

determining the median of the N sequential samples;

providing the median as an output sample; and

repeating the steps of examining a set of N sequential samples, determining the median, and providing the median.

48. The method of claim 47, further wherein the step of repeating further comprises examining a new set of N sequential samples of the received message signal;

wherein the new set of N sequential samples is determined by discarding the Nth sample of the N sequential samples and shifting the sequence of samples of the received message signal.

49. A method of filtering a received message signal comprising a sequence of samples, the method comprising the steps of:

examining a set of N sequential samples of the received message signal;

determining the median of the N sequential samples;

providing the median as an output sample; and

repeating the steps of examining a set of N sequential samples, determining the median, and providing the median.

50. The method of claim 49, further wherein the step of repeating further comprises examining a new set of N sequential samples of the received message signal;

wherein the new set of N sequential samples is determined by discarding the Nth sample of the N sequential samples and shifting the sequence of samples of the received message signal.