TB8100 Service Kit User’s Manual Monitoring Alarms 153Power Management UnitThe Power Management Unit area shows the alarm status of the PMU thatsupplies the base station with power.No PMU detected The reciter is unable to detect the PMU on the control bus. In subracks withmore than one reciter, only reciter 1 can communicate with the PMU. Forreciters other than reciter 1, this alarm should be disabled. There may be a faultor the PMU may still be operating satisfactorily. However, the system has lostthe ability to monitor PMU alarms, carry out diagnostics, change configuration,or detect PMU fan failure. Power saving is disabled.Fan failed The PMU told the reciter that its fan is on, but the reciter cannot detect fanmotion. The base station takes no action when this alarm occurs, but it will actif the PMU temperature becomes too high.The fan has failed. Replace it.ShutdownimminentThis alarm only appears if the PMU has a DC-DC converter and a Standbyconverter. A battery is currently being used to power the base station and itsvoltage has fallen to the absolute minimum. The PMU will stop operating 30seconds after activating this alarm.The main value of this alarm is as an input for Task Manager actions. You can,for example, have the base station send the alarm log just before shutting down.Mains supplyfailedThe AC mains power supply to the PMU is absent or its voltage is outsideacceptable limits. The PMU is using DC power from its battery source.Power up fault The PMU has detected an internal error and will reset itself. If the reset issuccessful, the alarm will clear.Temperature high One of the PMU temperature sensors has detected a temperature that is abovethe fixed limit.Battery The PMU measures the voltage of its battery input.Battery voltagehighThe PMU’s battery voltage is higher than the configured maximum. The basestation takes no action until the voltage reaches the fixed maximum, when itshuts down.Battery voltagelowThe battery voltage is below one of the configured minimums. (There are twoconfigurable minimum battery voltages, one for when the PA is transmittingand the other for when it is idle.) If the voltage falls further so that it is belowthe Power shutdown voltage (Configure > Base Station > Miscellaneous), thePMU will shut down to protect the battery.
