Method of transmitting a high-priority message in a lighting control system
First Claim
1. A method of transmitting a high-priority digital message via a communication link, the method comprising the steps of:
- transmitting regular-priority digital messages between a plurality of control devices including a master control device, a first control device, and a second control device;
the master control device transmitting a first regular-priority polling message to the first control device;
the first and second control devices simultaneously transmitting a respective break character by asserting the communication link for an amount of time during a predetermined time period following the first regular-priority polling message to signal that the first and second control devices have respective high-priority digital messages to transmit;
the master control device detecting the transmission of the break characters;
suspending the transmission of the regular-priority digital messages between the plurality of control devices;
the master control device determining a Poll ID of the first control device in response to detecting the assertion of the communication link;
the master control device transmitting a report-request message to the first control device using the Poll ID of the first control device;
the first control device transmitting the respective high-priority digital message in response to the report-request message during the suspension of the transmission of the regular-priority digital messages;
the master control device subsequently determining a Poll ID of the second control device;
the master control device transmitting a report-request message to the second control device using the Poll ID of the second control device; and
the second control device transmitting the respective high-priority digital message in response to the report-request message during the suspension of the transmission of the regular-priority digital messages.
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Accused Products
Abstract
A lighting control system having a plurality of control devices coupled to a communication link operates with a communication protocol that allows the system to expeditiously process high-priority events while operating communicate at a low enough baud rate to allow for a free-wiring topology of the communication link. The transmission of regular-priority messages is suspended if any of the control devices has a high-priority message to transmit. To signal that a control device has a high-priority message to transmit, each control device is operable to transmit a break character in a predetermined time period after the transmission of one of the digital messages. After the transmission of the break character, the transmission of the regular-priority messages on the communication link is suspended to allow the high-priority message to be transmitted quickly.
90 Citations
22 Claims
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1. A method of transmitting a high-priority digital message via a communication link, the method comprising the steps of:
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transmitting regular-priority digital messages between a plurality of control devices including a master control device, a first control device, and a second control device; the master control device transmitting a first regular-priority polling message to the first control device; the first and second control devices simultaneously transmitting a respective break character by asserting the communication link for an amount of time during a predetermined time period following the first regular-priority polling message to signal that the first and second control devices have respective high-priority digital messages to transmit; the master control device detecting the transmission of the break characters; suspending the transmission of the regular-priority digital messages between the plurality of control devices; the master control device determining a Poll ID of the first control device in response to detecting the assertion of the communication link; the master control device transmitting a report-request message to the first control device using the Poll ID of the first control device; the first control device transmitting the respective high-priority digital message in response to the report-request message during the suspension of the transmission of the regular-priority digital messages; the master control device subsequently determining a Poll ID of the second control device; the master control device transmitting a report-request message to the second control device using the Poll ID of the second control device; and the second control device transmitting the respective high-priority digital message in response to the report-request message during the suspension of the transmission of the regular-priority digital messages. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of transmitting high-priority digital messages from first and second devices on a communication link that links the first and second devices and a master device, the method comprising the steps of:
- the master device transmitting a first polling message;
the first and second device each transmitting a respective high-priority break character during a predetermined time period following the master device transmitting the first polling message;
the master device determining a unique link address of the first device in response to the first device transmitting the respective high-priority break character;
the master device determining a unique link address of the second device in response to the second device transmitting the respective high-priority break character;
the master device transmitting a second polling message to the first device in response to receiving the high-priority break character;
the first device transmitting a first high-priority digital message to the master device in response to the second message;
the master device subsequently transmitting a third polling message to the second device; and
the second device transmitting a second high-priority digital message in response to the third polling message. - View Dependent Claims (16, 17)
- the master device transmitting a first polling message;
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18. 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:
- sequentially transmitting a poll message to each of the plurality of control devices using the Poll ID of each control device;
at least two of the control devices simultaneously transmitting break characters in a predetermined time period following one of the poll messages;
suspending the sequential transmission of poll messages in response to the step of transmitting break characters;
determining which two of the plurality of control devices transmitted the break characters;
determining a Poll ID of each of the control devices in response to detecting the break characters;
transmitting request messages to the two of the plurality of control devices that transmitted the break characters; and
transmitting from the two of the plurality of control devices that transmitted the break characters high-priority digital messages in response to the request messages. - View Dependent Claims (19)
- sequentially transmitting a poll message to each of the plurality of control devices using the Poll ID of each control device;
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20. A method of polling a plurality of control devices by a master device selected from said plurality of control devices, the plurality of control devices each 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 as active in a list of Poll IDs, the poll message including a status request;
each of the control devices responding to the poll message when the respective Poll ID of the device matches one of the Poll IDs in the list of the poll message;
two of the control devices transmitting a high-priority request by asserting the communication link for an amount of time during a predetermined time period following the transmission of any poll message;
the master device interrupting the sequential transmission of poll messages when the high-priority request is received; and
the master control device determining a Poll ID of each of the two control devices in response to detecting the assertion of the communication link;
performing a binary search to find the respective Poll IDs of the two control devices that provided the high-priority requests during the interruption of the sequential transmission of poll messages.
- the master device sequentially transmitting a poll message to each control device marked as active in a list of Poll IDs, the poll message including a status request;
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21. A master control device for a lighting control system having a communication link coupled to a first and second control device, the master control device comprising:
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a communication circuit operable to be coupled to the communication link for transmission and receipt of digital messages; and a controller coupled to the communication circuit and operable to control the transmission and receipt of the digital messages; wherein the controller is further operable to; transmit a first regular-priority message; detect an assertion of the communication link by the first and second control devices for an amount of time during a predetermined time period following the transmission of the first regular-priority message signaling that the first and second control devices have respective high-priority digital messages to transmit; determine a Poll ID of the first control device; transmit a report-request message to the first control device using the Poll ID of the first control device; receive the respective high-priority digital message from the first control device; subsequently determine a Poll ID of the second control device; transmit the report-request message to the second control device using the Poll ID of the second control device; and receive the respective high-priority digital message from the second control device.
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22. A load control system comprising:
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first and second control devices coupled to a communication link and including a respective Poll ID, the first and second control devices operable to receive polling messages and to transmit regular-priority digital messages in response to the polling messages; and a master control device coupled to the communication link, the master control device operable to sequentially transmit the polling messages to the first and second control devices; wherein the first and second control devices each operable to simultaneously transmit high-priority break characters by asserting the communication link during a predetermined time period following one of the polling messages to signal that first and second control devices have respective high-priority digital messages to transmit; the master control device operable to detect the transmission of the high-priority break characters and to suspend the transmission of the regular-priority digital messages; the master control device operable to determine the Poll ID of the first control device in response to detecting the transmission of the high-priority break characters; the master control device operable to transmit a report-request message to the first control device using the Poll ID of the first control device; the first control device operable to transmit the respective high-priority digital message in response to the report-request message during the suspension of the transmission of regular-priority digital messages; the master control device operable to subsequently determine the Poll ID of the second control device and transmit the report-request message to the second control device using the Poll ID of the second control device; and the second control device is operable to transmit the respective high-priority message in response to the report-request message during the suspension of the transmission of regular-priority digital messages.
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Specification