[Stefan, Jamie, Kiwamu]
After a couple of small tweaks, the IMC came back to the point where it routinely locks.
Since there will be a couple of scheduled measurements tonight for HAM2/HAM3 HEPIs/ISIs/SUSs, we disabled the autolocker so as not to disturb the measurements and also not to drive the FSS crazily.
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Small Tweaks:
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H1:SUS-MC2_M3_LOCK_L_GAIN was decreased from -600 to -300.
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Since the LOCK filters had been changed to Livingston ones recently, the gain wasn't too high to have a cross over frequency of about 20 Hz.
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Currenlty FM3 and FM9 are used for acquiring its lock. Once it grabs a fringe FM2, which is a boost, needs to be turned on.
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H1:SUS-MC2_M2_LOCK_L_GAIN was set to be 0.2
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This was somehow found to be zero.
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Currently only FM4 is used.
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During the acquisition GAIN is set to be zero and needs to be ramped up to 0.2 once it is in lock.
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We checked the I and Q signals of the IMC length signal at the floor and made sure it hadn't changed.
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It seems the same as that we had before (alog 7181) on the oscilloscope.
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Therefore the WFS must be also the same as before.
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We enabled MC1/2/3_M1/2/3_LOCK_P/Y_OUTPUT such that the WFSs can act on the top mass of the MC suspensions.
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They were off for some reason and hence the WFSs wasn't properly working.
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The WFS loops seem working fine.
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We haven't do a characterization of the IMC lock loop after these little tweaks.
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At some point the cross over frequencies need to be revisited.