Auxiliary Alarm Lights

When an alarm condition occurs, any of the six auxiliary alarm lights may switch on, in addition to the main alarm light, to help diagnose the alarm condition. The following sections describe the six auxiliary alarm lights.

External Alarm (EXT ALARM)

The external alarm (labeled EXT ALARM) light switches on to indicate that an alarm condition has triggered the built-in relay outputs to turn on any externally installed alarms such as lights or bells.

The external alarm is connected to the matrix through the 9-pin D-type connector on the matrix’s rear panel labeled Alarm I/O.

Temp alarm (Temperature alarm)

The red Temp alarm light switches on to indicate one or both of the following:

  • The active CPU card has detected a temperature in the matrix above a threshold.

  • One of two CPU cards has been removed from the matrix.

Note: This feature only operates if there are two CPU cards installed in the matrix. If there is only one CPU card, the Temp alarm light does not switch on if the card is removed.

Fan-fail alarm

The red fan-fail alarm light illuminates when either fan in the power-supply module stops rotating correctly.

PSU1 Fail

When the first power supply unit is operating correctly, the red PSU1 light stays off, while the four green power supply lights (+12V, +5V, +3.3V, -12V) stay on continuously.

If a DC output or AC input to the first power supply drops too low, the red PSU1 light switches on. The amber (XP) or red (Power-One/Bel Fuse) light on the power supply unit itself also switches on to indicate the same condition. One of the green power supply lights may then switch off to help indicate the source of the trouble.

Note: The PSU1 fail light only works if the first power supply is plugged into the matrix’s midplane from inside the matrix.

A temperature sensor inside the power supply senses if the power supply overheats, and switches on the second matrix cooling fan. The red Temp light switches on to indicate that the active CPU card, not a power supply, has overheated.

PSU2 Fail

When the first power supply unit is operating correctly, the red PSU2 light stays off, while the four green power supply lights (+12V, +5V, +3.3V, -12V) stay on continuously.

If a DC output or AC input to the first power supply drops too low, the red PSU2 light switches on. The amber (XP) or red (Power-One/Bel Fuse) light on the power supply unit itself also switches on to indicate the same condition. One of the green power supply lights may then switch off to help indicate the source of the trouble.

Note: The PSU2 fail light only works if the first power supply is plugged into the matrix’s midplane from inside the matrix.

A temperature sensor inside the power supply senses if the power supply overheats, and switches on the second matrix cooling fan. The red Temp light switches on to indicate that the active CPU card, not a power supply, has overheated.

Fan-On alarm light

Two fans deliver forced air cooling to the matrix’s power supplies. The primary fan runs continuously. If a temperature exceeding a threshold is detected in a power supply and extra cooling is required, a second fan switches on to increase the air flow.

The fan-on alarm light illuminates red to indicate that the second fan is on.