Sheila, Vicky, Naoki

Recently we had several lockloss due to PI mode 29 ring up (80kHz PI). The PI guardian tried to damp it, but the PI kept ringing up and caused lockloss in ~5 minutes. We tried both common/diff ETMX actuation (LL:UR=1:1 and LL:UR=1:-1), but both of them failed. 

We modified the PI guardian for mode 29. We increased the damp gain to 50000. To have more time to evaluate the correct damping phase, we increased the phase step to 60 deg, the average time to calculate the new rms to 5s, and the timer for each step to 10s. We will see if this change helps in the next PI ring up.