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.

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.

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.

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.

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.