eleanor.king@LIGO.ORG - posted 10:07, Tuesday 18 August 2015 - last comment - 11:37, Tuesday 18 August 2015(20626)
Filter hardware added to ITM HWS power supply
Filiberto, Richard, Elli
A filter was added to the HWS power supply. The idea is that the filter module will cut out the current spikes from the HWS that were showing up in the PEM channels. We will test this today.
The filter is in a box labeled "HWS filter for power supply" and is located inside the HWS table by HAM 4, on top on the HWS corner breakout box. The filter connects between the HWS Corner Breakout Box (refer to D1200934 and E1100892).
I can't find any evidence of 1Hz lines or glitches when the ITM HWS cameras are on. The filter module appears to be doing its job.
There is no 1Hz glitxhes in the ITMX GS13 when the HWS is on. These glitches were bothering detchar during ER7 (alog 18548). The attached spectrogram can be compared with that in alog 18548. Left spectrogram is HWS off, right plot is with HWS on.
There is also no increase in the 1Hz line in the corner station magnetometer spectrum when the HWS cameras are switched on. (Spectrum attached. "Live" spectra were taken with camera off, reference spectra were taken with camera off.)