IS 2009-10-21 Clearified a bit.
IS 2012-03-19 Relaxed a bit due to new altaz and building drives.
How to deal with a power cut
This applies only if the power cut appears when the telescope is powered
In case of an external power cut, indicated by the warning message
'Security: NO EXTERNAL POWER! Notify duty staff.' and that
ventilation in the control room stops, there is no power to the cooling
system but the big UPS supplies the telescope with battery/diesel generator
power. That means that the telescope drive system will get heated up together
with all equipment in the electronics room. You can contact duty staff and
notify if the power cut lasts. Usually nightly power cuts are short, so
they do not effect the
observing, the TCS and its subsystems will continue to function. When the
power is back again the (friendly) error
message 'Security: External power is back again.' appears and
ventilation in the control room starts again. If the power cut lasts for
many minutes please do the following:
You are recommended to within 5-15 minutes save the ongoing exposure, put
telescope to zenith and power off. After a while the error
message 'Security: TEMPERATURE IN ELECTRONICS ROOM TOO HIGH!' might
show up. If You still have not gone to zenith and powered off then do it
now! The new altaz drives should be ok and the building drives also,
but the rotator amplifiers could be sensitive.
There could also be an automatic cut of the safety system if the temperature
in the electronics room raises further, caused by a thermostat. There is a
temperature display on top of rack 23 (last one to the left), have a look
When the message 'Security: External power is back again.' appears
then check the temperature on rack 23 until it is down to about 24 degrees,
then You can power on and continue to observe.
Note that if external power is only gone a few minutes there is usually no
need to take any special action. In very rare cases Residencia staff might
warn for a coming power cut, then just do as described above.
Please note the power cut down in the EON report.