Just like the work I did a couple weeks ago on HAM 4, today I tried to reduce cavity lengths by sending gnd z to HAM3 X. Seems like it works, although the high microseism has made getting good transfer functions difficult today. First attached plot is one of the plots I used to design the filter, but I literally just used the same zpk from the HAM4 z-x filter and matched the gain to the new transfer functions. The solid blue (or purple? I'm not sure) is the gnd Z to MCF transfer function over the HAM3 x drive to MCF transfer function. The red line is the filter I'm using at HAM4, the gold line is the filter for HAM3. The dashed line is the expected reduction. I tried several times to get the driven transfer function, looking at HAM3 x drive to IMC-F, PRCL, PRM and MC2 M3 length drives, and the filter design ended up being the same.
The second plot shows an on/off test with only PRMI with no arms. In this state PRCL and MC both see an improvement around the microseism. The dashed lines are with the Z-X sensor correction on, solid lines are with it off. Brown and green are the ground, which didn't change during the test. PRCL went from pink to orange (about 3x lower), MCF went from red to blue (almost 4x lower). Rana doesn't like my colors, and he has a calibrated spectra, so I might post that in a bit.
If people suspect this is causing problems it can be turned off like the SRCL sensor correction at the command line with:
caput H1:ISI-HAM3_SENSCOR_GND_STS_X_WNR_GAIN 0
For future operator and commissioner info, this is currently being used in:
- HAM3 X --> H1:ISI-HAM3_SENSCOR_GND_STS_X_WNR, gain of 1, only FM6 engaged
- HAM4 Y --> H1:ISI-HAM4_SENSCOR_GND_STS_Y_WNR, gain of 1, only FM6 engaged
For each of these chambers, you will need to:
- Set only the FM6
- Set these banks to a gain of 1
- The FIR path, parallel to the WNR path, also needs to be on in their respective dof.
- The STS matrix settings need to be set as seen in the attached screenshots.
(1st attachment is HAM3, second is HAM4)
TJ's settings are correct, but this should only be needed until this Tuesday or the next, whenever I can get the new sensor correction update installled. I had considered these settings "experimental" for the moment, hence I didn't capture it in SDF. Silly me.
I've captured these settings in the safe.snap. See attached screenshots for differences that I've accepted.
