with the environmental monitoring and reporting feature, you can keep your system running by resolving adverse environmental conditions before loss of operation.

    the power supply monitors its own internal temperature and voltages. in the event of excessive internal temperature, the power supply shuts down to prevent damage. when the power supply returns to a safe operating temperature, it restarts. if the power supply output voltage is not within the specified range, the led labeled output fail will light. an instance of substantial output overvoltage can shut down the power supply.

    an instance of substantial input overvoltage (greater than –75 v dc continuous) can damage the power supply input circuitry and can cause it to shut down permanently.

    for a 1400 w dc power supply, the main power switch has an input range of –40.5 to –72 v dc, while the –48 v poe operates over a range of –40.5 to –56 v dc. the poe either fails to start or shuts down if exposed to greater than –56 v dc input. poe recovers after you recycle input power within the proper voltage range. if the poe shuts down due to input overvoltage (greater than –56 v dc), the main converter section does not shut down.

    the supervisor engine monitors the status of each power supply and provides a status report through the switch software. for more details on how the supervisor engine monitors the power supplies, refer to the “environmental monitoring and power management” chapter of the catalyst 4500 series switch cisco ios software configuration guide.