Crystal Vision
Introduction
Indigo 4 User Manual R1.7
4
09/08/2012
There are four easily accessible front fans. Two are fitted on detachable plates in front of
the PSU modules and the other two are attached to the rear of the front panel.
On opening the front panel an optical sensor switches the PSU fans to fast operation and
the panel mounted fans are stopped by removing their power.
If one fan fails, or operates too slowly, the other fans are automatically switched to full
power and an alarm raised.
The frame internal temperature is monitored by sensors mounted at the rear of the upper
and lower middle bays, the fans speed is adjusted to maintain an optimum operating
temperature over a wide range of load and ambient temperatures.
There are three cooling modes: normal, quiet and maximum.
With normal cooling all fans run continuously, increasing in speed as the temperature
inside the frame goes up.
Quiet mode is intended for a lightly loaded frame in an environment where ambient noise
is a concern. When the frame temperature is below approximately 45°C the panel fans are
switched off and the PSU fans runs at minimum speed. If the frame temperature goes
above 45°C it reverts to normal cooling and goes back to quiet mode when the frame
temperature again falls below 42°C.
In Maximum cooling mode all four fans never run below near maximum speed. Fan speed
increases to maximum at high frame temperature. This mode is ideal for equipment bays
where noise is not a concern.
Only one fan in each of the upper and lower frames is essential in normal operation. If
one of the fans should fail, the closed frame can still operate indefinitely with an ambient
temperature of 40 °C.
Warning:
Although it is possible to operate the frame with the front panel open, the frame may not
meet electromagnetic compatibility (EMC) requirements in this condition.
All Indigo PSU modules have a built in processor, this processor (referred to as a PIC)
communicates with the front panel processor to pass on status information such as power
rail voltage levels (+5.75V and -6.0 V) and the PSU fan speed.
The panel processor regularly receives status updates from the PSU processors about
power rails and fan speed. This allows the front panel to update its status LEDs and
control the alarm changeover relay. The relay contacts are available on Remotes 2 and 8
connectors on the rear of the frame. If third and fourth PSUs are fitted, any alarms will
appear on Remotes 4 and 6.
There are ten two-colour LEDs on the front panel, with yellow/green indicating a normal
condition and red an abnormal condition. An eleventh LED indicates external comms
activity.
