Sheila, Kiwamu, Evan, Nergis, Alexa

We have been able to lock ALS DIFF for +20 min.

• Daniel's tidal feedback is engaged for both the X and Y-arm. This is successful in bringing the DIFF PLL into range. We need to update the SUS screens to show that the tidal feedback is engaged; right now it just shows a large L drive align input even if the L1_LOCK_OUTPUT is zero.
• We increased the LSC-DARM gain from 400 to 600. The OLTF has a UGF of 8 Hz with a phase of 75 deg; consistent with what we had previously.
• We decreased the L1_LOCK_L_GAIN from 0.5 to 0.28 (reverting an increase we had done previously), to bring the UIM/ESD crossover to 1Hz.
• The L2P and L2Y filters are just a flat gain of 5.2, and -0.7 respectively, with FM10 (-60dB) enagaged. The L2P is not that great. Some times we have more success with FM1(L2P), FM2(L2P2) ON, FM10 OFF and a gain of -1. However, this has a high Q, and we tend to kick ETMX more when we lose lock. 

I have attached screen shots of the ALS DIFF filter configuration. In addition, I have attached the ALS_DIFF Spectrum, UIM/ESD crossover, and OLTF. The ALS DIFF spectra shows that the noise is suffeciently low to move onto locking.