Tektronix SPG8000A, Руководство пользователя, Страница: 49 / 243

SPG8000A User Manual 35
Operate Instrument with Two Power Supplies (Option
DPW Only)
The standard instrument has one Power Supply module installed. With Option
DPW, a second hot - swappable, redundant (backup) Power Supply module is
provided. When two Power Supply modules are installed in the instrument, one is
configured as the primary supply and the other is configured as the backup supply.
If that the primary supply fails, the backup supply automatically provides power
to maintain instrument operation. You can remove and replace a failed supply
without having to remove the instrument from operation. (See To
hot-swap a Power Supply module
.)
Power Supply Status
The status of the Power Supply modules can be viewed from the front or rear of
the instrument. On the front panel, the PWR1 and PWR2 indicators illuminate
using various colors to show the status of the Power Supply modules. The rear
panel of each Power Supply module has a STATUS LED that matches the status
shown on the PWR1 and PWR2 indicators. See
SPG8000A Installation and Safety
Instructions
for information about the power supply status indicators.
You can use the SYSTEM menu to perform a load test on the backup supply and
to view voltage levels in the instrument.
Temperature weighted
hours (TWH)
The instrument keeps track of the age of a Power Supply module by calculating the
temperature weighted hours (TWH). You can view the TWH of each installed
supply using the SYSTEM : DIAGNOSTICS menu.
TWH calculation method:
When the outside air temperature is at 25 °C or cooler,
the Power Supply module is expected to last 15 years. As the outside air
temperature rises to the maximum operating temperature of 50 °C, the expected
life of the supply decreases to 5 years. Every hour, the instrument measures the
outside temperature and changes the temperature weighted hours count in
response t o the measured temperature.
When the TWH value reaches a value of 131,400, then the associated PWR1 or
PWR2 indicator will be set to orange to indicate that the supply should be replaced.
Note : When two Power Supply modules are installed, the active supply runs
warmer than the backup supply. Therefore, the TWH of the active supply will
increase faster than the backup supply.