I found the 9 sec timing error in the test mass charge measurement mentioned in LHO log 15983. See UR_timing_err.pdf. The problem was in the matlab analysis script, not in the python measuring script. The measurement script saved a seperate file for the excitations for each quadrant and bias level. See for example, UR_Exc_raw_data.pdf. The excitations in these files are preceded by 9 or 10 seconds and trailed by 3 or 4 seconds where the excitation is nominally zero. The analysis script then finds the exact point where the excitation starts by searching for the first point where the excitation data is non-zero. The problem is that the very beginning of the excitation is not always exactly zero because of some tiny residual from a previous excitation. The analysis code was aware of this problem, and therefore cut out the first second. However, 1 second was not always quite enough. Sometimes a non-zero data point or two would survive the 1 sec cut. So I extended this cut to 2 seconds. So far this removes the problem from all the analysis. See UR_timing_err_fixed.pdf.

The new trend results are in ETMY_Charge_Trend_8Jan2015.pdf. The timing error fix inf;luenced the pitch results by +- 5 volts and the yaw results by +- 15 V.

All charge scripts are on the SVN in

.../SusSVN/sus/trunk/QUAD/Common/Scripts/

The charge measuring script is

ESD_UL_LL_UR_LR_charge_07-H1.py

This scripted can be run on repeat many times using the script

ChargeTest_H1.py

It is set to repeat the measurement 10 times, waiting 5 minutes between runs (currently each run is about 10 minutes long).

The Matlab analysis script that processes the results is

ESD_UL_LL_UR_LR_analysis07_H1.m

There is a script for plotting trends over multiple measurements, but it needs some work to generalize it for different suspensions and different data sets.

Long_Trend_H1_ETMY.m

In log 15983 the date stamp of the trend figure should read Jan 8, not Jan 9.