Scanning method and system for a multiple light beam system

• US 20090129784A1
• Filed: 11/16/2007
• Published: 05/21/2009
• Est. Priority Date: 11/16/2007
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Lenoir, Jean Christophe, Simon, Jean-Luc, Carnicelli, Vito
• Granted Patent: US 7,960,681 B2
• Time in Patent Office: Days
• US Class Current: 398/154
• CPC Class Codes: G01V 8/20 using multiple transmitters or receivers

Abstract

A method and system for scanning a multiple light beam system, such as a safety light curtain, uses a plurality of transmission signals including two or more synchronization signals for synchronizing a beam receiver module with a beam transmission module. The system has transmitter circuitry which generates the transmission signals for driving light sources of the transmission module and receiver circuitry which receives corresponding transmitted signals. The receiver circuitry generates a scanning initialization signal using an uninterrupted synchronization signal among the reception signals for synchronizing the receiver module with the transmission module and scans the receiver module in response to generation of the scanning initialization signal.

Claims

1. A method for scanning a multiple light beam system having beam transmission and reception modules;

said method comprising

generating a plurality of transmission signals for driving respective light sources of the transmission module;

said plurality of transmission signals including at least two synchronization signals;

receiving corresponding signals transmitted from the transmission module;

detecting an uninterrupted synchronization signal among said reception signals;

synchronizing said receiver module with said transmission module using said detected uninterrupted synchronization signal in order to synchronize said multiple light beam system; and

scanning the receiver module synchronized with said transmission module.

2. The method of claim 1, further comprising

detecting another uninterrupted synchronization signal among said reception signals in response to detecting an interruption of said uninterrupted synchronization signal;

synchronizing said transmission module with said receiver module using said another uninterrupted synchronization signal in order to synchronize said multiple light beam system;

scanning said receiver module synchronized using said another uninterrupted synchronization beam.

3. The method of claim 1, further comprising

turning off said multiple light beam system in response to detecting interruption of all of said synchronization signals.

4. The method of claim 1, further comprising encoding each synchronization signal for transmission in a different format.

5. The method of claim 1, wherein said at least two synchronization signals comprise a master synchro signal and a slave synchro signal and further comprising

detecting interruption of said master synchro among said reception signals;

detecting an uninterrupted slave synchro signal among said reception signals;

generating a simulated synchro signal using said uninterrupted slave synchro signal; and

synchronizing said receiver module with said transmission module using said simulated synchro signal in order to synchronize said multiple light beam system.

6. The method of claim 5, further comprising

following synchronizing said receiver module with said transmission module using said simulated synchro signal, detecting an uninterrupted master synchro signal among said reception signals;

and

synchronizing said receiver module with said transmission module using said master synchro signal in order to synchronize said multiple light beam system.

7. A method for scanning a multiple light beam system having beam transmission and reception modules for transmitting and receiving light beams, respectively;

said method comprising

generating a plurality of transmission signals for driving respective light sources of the transmission module;

said plurality of transmission signals including at least two synchronization signals;

receiving corresponding signals transmitted from the transmission module;

generating a scanning initialization signal using an uninterrupted synchronization signal among said reception signals for synchronizing said receiver module with said transmission module; and

scanning said receiver module in response to receiving said scanning initialization signal.

8. The method of claim 7, wherein said synchronization signals comprises a master and a slave synchro signals;

and further comprising;

generating said scanning initialization signal using an uninterrupted master synchro signal for synchronizing said receiver module with said transmission module; and

generating another scanning initialization signal using an uninterrupted slave synchro signal among said reception signals in response to detecting omission of said master synchro signal among said reception signals.

9. The method of claim 8, further comprising generating yet another scanning initialization signal using said uninterrupted master synchro signal for re-synchronizing said transmission module with said receiver module in response to re-detecting said uninterrupted master synchro signal among said reception signals.

10. The method of claim 7, further comprising

turning off said multiple light beam system in response to detecting omission of all of said synchronization signals among said reception signals.

11. The method of claim 7, further comprising encoding each synchronization signal for transmission in a different format.

12. The method of claim 11, further comprising

encoding the master synchro and slave synchro signals differently, and

including a different or similar message in each of said master synchro and said slave synchro signals.

13. A scanning system for scanning multiple light beams systems, said scanning system having:

transmitter circuitry adapted and arranged to generate a plurality of transmission signals for driving respective light sources of a beam transmission module;

said transmission signals including a plurality of synchronization signals; and

receiver circuitry adapted and arranged to

receive corresponding signals transmitted from the beam transmission module to a beam receiver module, and

generate a scanning initialization signal using an uninterrupted synchronization signal among said reception signals for synchronizing said beam receiver module with said beam transmission module; and

initiate scanning of said beam receiver module using said scanning initialization signal.

14. The system of claim 13, wherein said synchronization signals comprise master and a slave synchro signals;

and wherein said receiver circuitry is adapted and arranged to;

generate said scanning initialization signal using an uninterrupted master synchro signal for synchronizing said receiver module with said transmission module; and

generate another scanning initialization signal using an uninterrupted slave synchro signal among said reception signals in response to detecting omission of said master synchro signal among said reception signals.

15. The system of claim 14, wherein said receiver circuitry is adapted and arranged to generate yet another scanning initialization signal using said uninterrupted master synchro signal for re-synchronizing said transmission module with said receiver module in response to re-detecting said uninterrupted master synchro signal among said reception signals.

16. The system of claim 13, wherein said receiver circuitry is further adapted and arranged to turn off said multiple light beam system in response to detecting omission of all of said synchronization signals among said reception signals.

17. The system of claim 13, wherein said receiver circuitry is further adapted and arranged to encode each synchronization signal for transmission in a different format.

18. The system of claim 13, wherein said receiver circuitry is further adapted to include a different or similar message in each of said master synchro and said slave synchro signals.

19. The system of claim 13, wherein said multiple light beam system comprises a safety light curtain.

20. The system of claim 19, wherein said transmission module comprises a column of infra red lights sources and said receiver module comprises a column of corresponding infra red detectors.