Channel Configuration Logger

LIGO’s real-time control loops are based on the Experimental Physics and Industrial Constrol System (EPICS), which at any given time is attempting to track the configuration in software of tens of thousands of data streams (or channels). The channel configuration logger, called Conlog, is a sophisticated system that identifies sudden changes by analyzing readback channels. The version of Conlog implemented here is scaled-back, simplified, and run in python on the command-line.

Command-line utility


This utility requires authentication with LIGO.ORG credentials for archived frame data access.


For a full explanation of the available command-line arguments and options, you can run

$ python -m gwdetchar.conlog --help
usage: python -m gwdetchar.conlog [-h] [-V] -i IFO [-f FRAMETYPE] [-j NPROC]
                                  [-o OUTPUT] [-c CHANNELS]
                                  [-s [SEARCH [SEARCH ...]]] [-p PREVIEW]
                                  gpsstart gpsend

Check whether state records have changed between two reference times

positional arguments:
  gpsstart              GPS start time or datetime of analysis
  gpsend                GPS end time or datetime of analysis

optional arguments:
  -h, --help            show this help message and exit
  -V, --version         show program's version number and exit
  -i IFO, --ifo IFO     IFO prefix for this analysis, default: None
  -f FRAMETYPE, --frametype FRAMETYPE
                        the frametype name, defaults to second trends for the
                        selected interferometer
  -j NPROC, --nproc NPROC
                        the number of processes to use when reading data,
                        default: 8
  -o OUTPUT, --output OUTPUT
                        Path to output data file, default: changes.csv
  -c CHANNELS, --channels CHANNELS
                        file containing columnar list of channels to process,
                        default is to find all relevant channels from frames
  -s [SEARCH [SEARCH ...]], --search [SEARCH [SEARCH ...]]
                        process channels matching these regex patterns, can be
                        given multiple times, default is to analyze all
                        relevant channels from frames
  -p PREVIEW, --preview PREVIEW
                        Time (seconds) over which to test that channel is
                        normally kept constant, default: 10