Light curtain safety system

A system to detect obstacles to a power beam using frequency domain multiplexing of a plurality of emitter signals, comprising:

• a plurality of emitters and a plurality of detectors that form a light curtain patterned about the power beam, the plurality of emitters surrounding the power beam having an emitter module including:
• one or more first emitters arranged to modulate a first guard beam signal at a first frequency, the first guard beam signal emitted in proximity to the power beam;
• and
• one or more second emitters arranged to modulate a second guard beam at a second frequency, wherein the first frequency is different than the second frequency, the second guard beam signal emitted in proximity to the first signal;
• and
• the plurality of detectors surrounding the power beam, the plurality of detectors including:
• one or more first detectors arranged to detect a first guard beam signal emitted by the one or more first emitters at the first frequency;
• one or more second detectors arranged to detect a second guard beam signal emitted by the one or more second emitters at the second frequency,
• a controller that directs operations of one or more first detectors and one or more second detectors,
• wherein the controller determines that an absence of a first guard beam signal or a second guard beam signal is indicative of a foreign object near or impeding the power beam.

A system to detect obstacles to a power beam using wavelength domain multiplexing of a plurality of emitter signals, comprising:

• a plurality of emitters and a plurality of detectors that form a light curtain patterned about the power beam, the plurality of emitters surrounding the power beam having an emitter module including:
• one or more first emitters arranged to modulate a first guard beam signal at a first wavelength, the first guard beam signal emitted in proximity to the power beam;
• and
• one or more second emitter arranged to modulate a second guard beam at a second wavelength, wherein the first wavelength is different than the second wavelength, the second guard beam signal emitted in proximity to the first signal;
• and
• the plurality of detectors surrounding the power beam, the plurality of detectors including:
• one or more first detectors arranged to detect a first guard beam signal emitted by the one or more first emitters at the first wavelength;
• one or more second detectors arranged to detect a second guard beam signal emitted by the one or more second emitters at the second wavelength,
• a controller that directs operations of one or more first detectors and one or more second detectors,
• wherein when an expected signal of a particular wavelength is not received, the controller determines that is indicative of a foreign object near or impeding the power beam.