StrainWatch

StrainWatch monitors the interferometer and calcuates h(t), alpha, beta, and alphabeta in realtime. It is based on the ComputeStrain program (written by Xavier Siemens <siemens@gravity.phys.uwm.edu>), which can be found in the lal and lalapps library, but adapts it to run in realtime. Segments of raw interferometer data are obtained from the DMT environment and put through an IIR filter, out of which h(t) is calculated. For details on how this is done, see the article on Siemens' original program at http://arxiv.org/abs/gr-qc/0405070.

StrainWatch integrates this preexisting lalapps program with the DMT environment to process h(t) in realtime. Every second it processes a chunk of data of n seconds length, applies the IIR filtering, and computes h(t) and the factors. In so doing, only (n-2w) seconds of valid h(t) are generated; thus the generation of h(t) lags behind the input data by w seconds. W, referred to as the wings, can be set on the command line. For a more complete explanation of the reason for this invalid data, see the above article by Siemens.

Questions?

Any questions or concerns regarding this program may be address to Ramon Armen at <rarmen@umich.edu>.


Command line arguments:

Note: only -ifo is required
-ifo <name>
	The interferometer to monitor. Name is one of H1, H2, or L1. Required argument.

-config <file>
	A config file, containing command line arguments in the same format as that given here.
	The config file can also have commented lines, which should start with a '#' sign.

-help
	Prints help information

-stride <num_seconds>
	Number of seconds between successive calculations. Do not use if you want a continuous run.

-asq <channel_name>
	Channel to use to get the AS_Q data. Default is LSC-AS_Q

-exc <channel_name>
	Channel to use to get the excitation data. Default is ##:LSC-DARM_CTRL_EXC_DAQ

-darm <channel_name>
	Channel to use to get the darm data. Default is ##:LSC-DARM_CTRL

-darmerr <channel_name>
	Channel to use to get the darm error data. Default is ##:LSC-DARM_ERR

-lock <condition>
	Conditions to require before processing data. Default is ##:Both_arms_locked_strict_cm

-OSCfile <filename>
	File with operating state condition definitions. Default is LockLoss.conf

-downsample <factor>
	If it is taking too long to process data, you may downsample the data.
	For optimal performance, this should be a power of 2. Default is no downsampling.