Significant State Of Health variables for ANUBIS stations
More than half the ANUBIS stations are installed (7 out of the eventual 12 stations). Of these seven, four have been reliably transmitting SOH data. The other stations were all working when we left the site (and based on our experience with the other sites, we believe they are still working). SDM = Siple Dome, CWA = Central West Antarctica, ISDE = Ice Stream DE, MBL = Marie Byrd Land, BYRD = Byrd Surface Camp, MTM = Mt. Moore, and AGO2 = AGO-2. These plots are updated once a day. The last twenty days of data from the ARGOS satellite system are displayed. Of the two dozen variables that are transmitted, the most important are
This is the battery voltage. We use four sealed lead acid gel
cells that should maintain a voltage of about 13.85V (at 10C).
The system electronics will deplete this charge (unless
the batteries are being recharged by wind- or
solar-energy) and the voltage
will drop as low as 11.5V. At this point the electronics are shut
off to prevent damage to the batteries.
This is the temperature inside the instrument shelter. The power
system is designed to maintain at least a +10C temperature. If
the wind- or sun-generated current is too low to both charge the
batteries and heat the box, this temperature will drop. On the
other hand, if the outside temperature is high the heat
generated by the electronics will tend to raise the temperature
above 10C.
This is the temperature outside the instrument in degrees
Celsius. We use an instrument case built of 4 inches of
blueboard, some airspace, and then the inner instrument case with
1 inch of closed-cell foam to provide some insulation. The whole
case is sitting on the surface of the snow (unless it has drifted
in by now). We have an active heating element driven by
wind-generators and solar panels to maintain the instrument
temperature at +10C.
This is the charging/heating/dump current provided by one of
the two wind generators. This current is directed to the
batteries until they attain their float voltage. The current is
then tapered off and ramps up to the heater inside the
instrument. When the internal temperature reaches +10C, the
current is tapered off and re-directed to a heating plate outside
the shelter. Due to a wiring error, these numbers are
incorrect for ISDE, MBL, and CWA (there is a non-linear scale
factor that "stretches" the numbers to higher values).
This is the charging/heating/dump current provided by one of
the two solar panels. See above for an
explanation of how the current is used. Due to a wiring error,
these numbers are
incorrect for ISDE, MBL, and CWA (there is a non-linear scale
factor that "stretches" the numbers to higher values).
This is the wind speed in meters per second (m/s). Multiply
by two to get the approximate wind speed in knots.
This is the number of times that the disk has been accessed
since the last bootup of the system. In an ideal world this
number will increase monotonically from 0! Each write fills up
about 1.9MB of disk space. Note that the slopes should be approx
the same on all the graphs, but isn't. My guess is that some
sites are noisier than others, resulting in poorer compression of
the data and thus more space is being used in the same amount of time.
This is the percentage of the disks that has been used. For
redundancy, each site has two disks that will be mirrors of each
other. They are 8GB capacity IDE hard disks. The use of hard
disks is one of the most failure-prone parts of the system.
However, until flash memory is available in these large
capacities, we will have to continue to try and create "livable"
environments for the disks in the middle of the Harshest Place On
Earth!
