Low resolution housekeeping data¶
Overview¶
For studies on long (>1 minute) time scales, the housekeeping data recorded by AMCP are stored at reduced resolution in text format and can be loaded by moby2. The interface is based on the one used to load APEX weather data.
The data that this module makes available must be compiled from the full-resolution dataset. This occurs automatically on raid for the current season. For past seasons the most up-to-date archive is probably on feynman.
Recipes¶
See APEX weather data for more examples of how this sort of thing works. An example, though, is:
import moby2
chan_el = moby2.aux_data.hk.HKChannel('Enc_El_Deg')
el, dt = chan_el.get_nearest(1417046400)
print (el, dt)
(59.990000000000002, 33.0)
This means that the nearest data to ctime 1417046400 was 33 seconds later, and at that time the Enc_El_Deg field was reading 59.99 degrees.
Note that the “dt” result effectively carries the validity of the data. The user must always check the time difference between requested and returned data, to confirm it is within acceptable tolerances. AMCP is not always running, and even when it is it might have been set to not acquire the data you are asking for. So check dt to make sure it’s within the tolerance of your application.
A more complex example: Look up a bunch of values at once, and screen them for validity using a boolean mask based on dt.
# Initialize the looker-up.
import moby2
import numpy as np
chan_el = moby2.aux_data.hk.HKChannel('Enc_El_Deg')
# Create a vector of ctimes covering October 2014, in 10 minute spacing.
t0 = moby2.util.ctime.from_string('2014-10-01 0:0:0')
t1 = moby2.util.ctime.from_string('2014-11-01 0:0:0')
ctimes = np.arange(t0, t1, 10*60)
# Look-up the elevation and observation time offset at each time. Since
# we pass in a vector of ctimes, the returned values el and dt are also
# vectors.
el, dt = chan_el.get_nearest(ctimes)
# Keep only the data that are less than 20 minutes out of date.
mask = (abs(dt) < 20*60)
el, dt = el[mask], dt[mask]
Configuration¶
For sensible default behavior, your .moby2 file should contain a block with the path to the local APEX data archive:
On galahad/raid:
APEX_weather = {
'targets_directory': '/dataz/aux_data/hk_lowres/',
'ctime_range': [1370000000, 2000000000],
}
On feynman:
HK_lowres = {
'targets_directory': '/mnt/act3/users/mhasse/depots/mhasse0/hk_lowres/',
'ctime_range': [1370000000, 2000000000],
}
On tigercpu/della:
HK_lowres = {
'targets_directory':
'/projects/ACT/mhasse/depots/actpol_shared/aux_data/hk_lowres',
'ctime_range': [1370000000, 2000000000],
}