Communication network with arrangement for replacing a malfunctioning active master with a new active master

1. A communication network, comprising

a plurality of devices, each device comprising:

a device operating circuit,

a communication interface for receiving command signals for controlling an operation of the device operating circuit,

a control circuit coupled between the device operating circuit and the communication interface for controlling the operation of the device operating circuit in response to said command signals, and

a master integral to the device for receiving control signals; and

a control unit for generating the control signals,

wherein the communication network activates one of the masters as an active master for generating the command signals in response to the received control signals, and for transferring the command signals to the communication interfaces of the plurality of devices, and in case the active master fails, the communication network activates a second one of the masters as the active master for generating the command signals in response to the received control signals, and for transferring the command signals to the communication interfaces of the plurality of devices.

2. The communication network of claim 1 , wherein the control unit is a wireless remote control unit, and the wireless remote control unit wirelessly communicates the control signals to the masters of the devices.

3. The communication network of claim 1 , wherein each master is equipped with a transceiver for wireless communication between the control unit and the master and between the master and the communication interfaces of the devices.

4. The communication network of claim 1 , wherein in at least one of the devices, the device operating circuit comprises a ballast circuit for operating a lamp.

5. The communication network of claim 4 , wherein in the at least one device includes a luminaire.

6. The communication network of claim 1 , wherein each master includes

beacon means for transmitting periodical signals when it is the active master; and

detecting means for detecting the periodical signals transmitted by the active master.

7. The communication network of claim 6 , wherein the detecting means comprise a timer circuit for timing a time lapse during which the periodical signal is absent.

8. The communication network of claim 7 , wherein each of the masters includes means for activating itself in case the active master fails.

9. The communication network of claim 8 , wherein the means for activating itself operates to activate itself when the time lapse during which the periodical signal is absent is longer than a predetermined time lapse.

10. The communication network of claim 1 , wherein each of the masters includes a table stored in memory that relates the received control signals to the command signals.

11. A method of operating a communication network having a plurality of devices, the method comprising:

activating a first master included in one of the plurality of devices to become an active master;

receiving control signals at the active master from a control unit;

in response to the control signals, transmitting command signals from the active master to the plurality devices to control operations of the devices;

detecting at a second one of the devices when the active master fails;

in response to detecting that the active master has failed, activating a second master included in the second one of the devices to replace the active master and to respond to the control signals by transmitting the command signals to the plurality devices to control operations of the devices.

12. The method of claim 11 , wherein the active master transmits the command signals wirelessly to at least some of the plurality of devices.

13. The method of claim 11 , wherein the active master transmits a periodic beacon signal to indicate that it is active and operating.

14. The method of claim 13 , wherein detecting at a second one of the devices when the active master fails comprises detecting that the beacon signal is absent for a time period greater than a threshold time period.

15. The method of claim 11 , wherein one of the operations of the devices is an illumination operation.

16. The method of claim 11 , wherein the control unit is a user-operated remote control unit that generates the control signals, and wherein receiving the control signals at the active master from the control unit comprises receiving the control signals wirelessly from the user-operated remote control unit, where the user-operated remote control unit generates the control signals in response to a user input.

17. The method of claim 11 , further comprising:

detecting at a third one of the devices when the second master fails;

in response to detecting that the second master has failed, activating a third master included in the third one of the devices to replace the second master and to respond to the control signals by transmitting the command signals to the plurality devices to control operations of the devices.

18. The method of claim 11 , further comprising accessing a table stored in memory at the active master to determine the command signals from the received control signals.

19. A network, comprising:

a plurality of devices, each device comprising:

a ballast circuit and a lamp connected to the ballast circuit,

a communication interface for receiving command signals for controlling an operation of the ballast circuit and lamp,

a control circuit coupled between the ballast circuit and lamp and the communication interface for controlling operations of the ballast circuit and lamp in response to said command signals, and

a master integral to the device for receiving control signals; and

a remote control unit for generating and transmitting the control signals, the remote control unit being remotely located with respect to the plurality of devices,

wherein the communication network activates one of the masters as an active master for receiving the control signals wirelessly from the remote control unit, and in response thereto for generating the command signals, and for communicating the command signals to the communication interfaces of the plurality of devices, and

wherein when the active master fails, the communication network activates a second one of the masters as the active master for generating the command signals in response to the received control signals, and for communicating the command signals to the communication interfaces of the plurality of devices.