jeffrey.bartlett@LIGO.ORG - posted 11:06, Thursday 18 April 2013 - last comment - 12:49, Thursday 18 April 2013(6126)
Phase 1b Testing I1-PRM
Andres R. & Jeff B. We completed taking the Transfer Functions and Power Spectra data for I1-PRM. The data files are attached below. There is a small peek at 0.85Hz, which is suppressed under damping. All scripts and data files have been committed to the SVN repository. We will wait for the testing group to review the results data before taking additional action on I1-PRM.
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Comments related to this report
It would appear that the undamped TF measurement (2013-04-17_1050277177_X1SUSPRM_M1_ALL_TFs.pdf) has been accidentally omitted from the original comparison plot (allhstss_2013-04-17_Phase1b_X1PRM_ALL_ZOOMED_TFs.pdf). I've therefore re-processed the comparison, this time including the undamped TF measurement, see plot attached below. The key for the relevant traces are as follows:- Blue trace = Model Prediction. Red trace = X1 PRM (2013−04−17_1050277177), Phase 1b. Undamped. Yellow trace = X1 PRM (2013−04−17_1050295239), Phase 1b. damped. The TFs taken for the I1-PRM show good agreement with the model and are consistent with measurements taken for other HSTS suspensions, at both sites, during the same phase of testing. The ~0.85 Hz feature observed by Jeff B coupling into roll and pitch DOFs I believe is the first vertical mode, which appears particularity energetic (maybe due to noise or excitation), with its energy bleeding into the other DOFs. Hence, damping loops suppress this feature. Therefore, PRM is approved for India. n.b. As of this entry I have committed the updated plots and scripts to the SUS svn (so please svn up the X1 test-stand).
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