COMMUNICATION PROTOCOL FOR A LIGHTING CONTROL SYSTEM

• US 20080191837A1
• Filed: 02/08/2007
• Published: 08/14/2008
• Est. Priority Date: 02/08/2007
• Status: Active Grant

• Current Assignee: Lutron Technology Company LLC
• Original Assignee: Lutron Electronics Company Incorporated (Lutron Electronics)
• Inventors: Stocker, R. Paul
• Granted Patent: US 8,306,051 B2
• Time in Patent Office: Days
• US Class Current: 340/3.51
• CPC Class Codes: H04L 12/40045 Details regarding the feeding of energy to the node from the bus
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling
• CPC Class Codes: H04L 61/5038 for local use, e.g. in LAN or USB networks, or in a controller area network [CAN]
• CPC Class Codes: H05B 47/175 by remote control
• CPC Class Codes: H05B 47/18 via data-bus transmission
• CPC Class Codes: H05B 47/195 the transmission using visible or infrared light

Abstract

A communication protocol for a lighting control system having a plurality of control devices coupled to a communication link uses a polling technique to coordinate the transmission of digital messages between the control devices. When the control devices are powered up, one of the control devices is established as a “master” device. During normal operation, the master device transmits a standard poll message to each of the control devices in succession using a unique semi-permanent Poll ID for each of the control devices. The master device periodically transmits a Poll-ID-Request poll message to the control devices allow those devices that do not have a Poll ID to request a Poll ID. If a control device determines either that the master device is not transmitting poll messages to it, or that another control device has the same Poll ID, the control device drops its Poll ID and acquires another Poll ID.

Claims

1. A method of polling a plurality of control devices by a master device selected from said plurality of control devices, each of the plurality of control devices coupled to a communication link and including a unique Poll ID, the method comprising the steps of:

the master device sequentially transmitting a poll message to each control device marked active in a list of Poll IDs;

each of the control devices responding to the poll message when the Poll ID of the device matches the Poll ID of the poll message;

the master device periodically transmitting a Poll-ID-Request poll message to the plurality of control devices; and

each of the control devices responding to the Poll-ID-Request poll message if the Poll ID of the control device is not marked active in the list of Poll IDs of the master device.

2. The method of claim 1, further comprising the step of:

prior to the step of the master device sequentially transmitting a poll message, building the list of Poll IDs indicating the control devices to which poll messages should be transmitted, a status of each control device on the list being marked active.

3. The method of claim 2, further comprising the step of:

assigning a unique Poll ID to each of the plurality of control devices by generating each Poll ID using a unique serial number of each of the plurality of control devices.

4. The method of claim 3, further comprising the step of:

coupling a second communication link to the first communication link, the second communication link having a second plurality of control devices coupled to it.

5. The method of claim 3, wherein the serial number is permanently assigned to each of the plurality of control devices by a device manufacturer.

6. The method of claim 3, wherein the serial number is 32-bits.

7. The method of claim 1, further comprising the steps of:

the master device marking the status of a control device as missing instead of active if the control device did not respond for a predetermined number of times to a poll message transmitted to the control device; and

making the Poll ID of the control device marked as missing available for re-assignment to other devices coupled to the communication link.

8. The method of claim 1, further comprising the steps of:

the master device marking the status of a control device as missing instead of active if the response from a control device is invalid a predetermined number of times; and

making the Poll ID of the control device marked as missing available for re-assignment to other devices coupled to the communication link.

9. A method of communicating a digital message from a first control device to a second control device, the method comprising the steps of:

the first device establishing itself as a master device;

the first device selecting a first Poll ID;

the first device transmitting a Poll-ID-request poll message;

the second device transmitting a break character in a predetermined time period following the first device transmitting the Poll-ID-request poll message;

the first device transmitting a second Poll ID to the second device in response to the break character; and

the first device transmitting the digital message to the second device using the second Poll ID.

10. The method of claim 9, further comprising the step of:

the first device determining a serial number of the second device in response to the second device transmitting the break character, prior to the step of the first device transmitting a second Poll ID to the second device.

11. The method of claim 10, wherein the step of the first device determining a serial number of the second device comprises the first device executing a binary search routine.

12. The method of claim 11, wherein the step of the first device executing a binary search routine further comprises the steps of:

the first device transmitting a Serial-Number-Search poll message including a search range of serial numbers;

the second device determining whether the serial number of the second device is within the search range of serial numbers; and

the second device transmitting a search break character in a predetermined time period following the first device transmitting the Serial-Number-Search poll message when the serial number of the second device is within the search range of serial numbers.

13. A method of polling a plurality of control devices on a communication link, each of the plurality of control devices having a unique Poll ID, the method comprising the steps of:

transmitting a first poll message to a first control device of the plurality of control devices using the Poll ID of the first control device;

receiving a response to the first poll message from the first control device;

transmitting a Poll-ID-request poll message to the plurality of control devices;

receiving a break character during a predetermined time period following the Poll-ID-request poll message from a second control device;

executing a search routine to determine the Poll ID of the second control device; and

transmitting a new Poll ID to the second control device.

14. The method of claim 13, further comprising the step of:

transmitting a break character during the predetermined time period following the Poll-ID-request poll message, prior to the step of receiving a break character.

15. The method of claim 14, wherein the step of transmitting a break character further comprises more than one of the plurality of control devices simultaneously transmitting a break character in the predetermined time period following one of the poll messages.

16. A method of acquiring a new Poll ID by a control device coupled to a communication link, the control device having an initial Poll ID, the method comprising the steps of:

receiving a poll message including the initial Poll ID;

listening for a response to the poll message transmitted on the communication link;

dropping the initial Poll ID if a response to the poll message is heard on the communication link;

receiving a Poll-ID-request poll message;

transmitting a break character in response to the step of receiving a Poll-ID-Request poll message; and

receiving the new Poll ID.

17. The method of claim 16, further comprising the steps of:

receiving a Poll-ID-search poll message; and

transmitting a break character in response to the step of receiving a Poll-ID-Search poll message.

18. A method of acquiring a new Poll ID by a control device coupled to a communication link, the control device having an initial Poll ID, the method comprising the steps of:

receiving a predetermined number of sequential poll messages that do not include the initial Poll ID;

dropping the initial Poll ID in response to the step of receiving a predetermined number of sequential poll messages that do not include the initial Poll ID;

receiving a Poll-ID-Request poll message;

transmitting a break character in response to the step of receiving a Poll-ID-Request poll message; and

receiving the new Poll ID.

19. The method of claim 18, further comprising the steps of:

receiving a Poll-ID-Search poll message; and

transmitting a break character in response to the step of receiving a Poll-ID-Search poll message.

20. A method of linking two lighting control systems comprising the steps of:

providing a first communication link coupled to a first control device having a first link address;

providing a second communication link coupled to a second control device having a second link address, the second link address the same as the first link address;

coupling the first communication link to the second communication link;

the first control device determining that the second link address of the second control device is the same as the first link address;

the first control device dropping the first link address in response to the step of determining; and

the first control device obtaining a third link address, the third link address different than the second link address.

21. The method of claim 20, wherein the step of obtaining a third link address further comprises the steps of:

receiving a Poll-ID-request poll message;

transmitting a break character in response to the step of receiving a Poll-ID-Request poll message; and

receiving the third Poll ID.

22. The method of claim 21, wherein the step of obtaining a third link address further comprises the steps of:

receiving a Poll-ID-search poll message; and

transmitting a break character in response to the step of receiving a Poll-ID-Search poll message.

23. The method of claim 20, wherein the step of determining further comprises the steps of:

the first control device receiving a poll message including the first Poll ID;

the first control device listening for a response to the poll message transmitted on the communication link; and

the first control device determining that the second link address of the second control device is the same as the first link address if a response to the poll message is heard on the communication link.