Create buffer for board saturation search window

Creates config.BOARD_SAT_BUFFER, which adds a buffer before the refined lockloss time in which to search for analog board saturations.

This is provided largely as a temporary fix for the LLO site, until we can get a better refinement procedure for them. Does not change LHO's board saturation checks.

locklost/config.py

@@ -208,6 +208,11 @@ ANALOG_BOARD_CHANNELS = ['%s:%s' % (IFO, chan) for chan in ANALOG_BOARD_CHANNELS
 
 BOARD_SEARCH_WINDOW = [-30, 5]
 
+if IFO == 'H1':
+    BOARD_SAT_BUFFER = 0
+if IFO == 'L1':
+    BOARD_SAT_BUFFER = 0.5
+
 BOARD_SAT_THRESH = 9.5
 
 ADS_CHANNELS = []

locklost/plugins/board_sat.py

@@ -31,7 +31,7 @@ def check_boards(event):
     for buf in board_channels:
         srate = buf.sample_rate
         t = np.arange(segment[0], segment[1], 1/srate)
-        before_loss = buf.data[np.where(t<event.gps)]
+        before_loss = buf.data[np.where(t<event.gps-config.BOARD_SAT_BUFFER)]
         if any(abs(before_loss) >= config.BOARD_SAT_THRESH):
             saturating = True
             glitch_idx = np.where(abs(buf.data) > config.BOARD_SAT_THRESH)[0][0]