• Communicates the beamline status to the APS-controlled front-end EPS (FEEPS) and causes the front-end safety shutter to close and/or be inhibited from opening if a dangerous beamline condition is detected. In return, the FEEPS sends a signal to the beamline EPS indicating the status of the front-end section.
• Communicates the beamline status to the personnel safety system (PSS) and causes the photon shutter PS112 located in the FOE to close and/or be inhibited from opening when a problem in a section downstream from that shutter is detected. IN return, the PSS indicates its status to the BLEPS.
• Monitors all ion pumps along the beamline and isolates a vacuum problem by closing the surrounding gate valves.
• Monitors cooling water flow through optical components that are not monitored by the FEEPS.
• Monitors limit switches on movable devices such as the white beam slit, the monochromator, the mirrors and beam pipe articulation drivers. On detecting a limit switch activation the BLEPS stops and inhibits all motor movements that could cause the fault and signals the beamline control computer to abort all current requests from moving these motors.
• Communicates its status to the beamline control computer.

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