This morning ETMX HEPI tripped again after a lock loss. Sheila and I looked into it and it looks like there is some difference between the tidal controls between the two arms. The first screen shows a number of signals related to the X arm tidal. After the lockloss (where the TRX power green(?) trace goes to zero in the center left) HEPI starts bleeding off the tidal offset. It looks like some flash makes the ALS think the arm is locked again, and it sends an 80 micron kick to the HEPI ISC offload (the big downward jump in the red trace, bottom left). The next two, traces are the request and states for the ALS X and Y for 5 seconds around the time of the HEPI trip. The second screen shows the state and request for Y, the notch in the black trace is the lock loss. The red trace shows the request going from (I think) Locked to Transition to Down (or something like that). The third screen shows the same time for the X arm. The state goes from Locked to Down, then 2 seconds later the Request goes from Locked to Down, which cause the State to jump back up to Locked, then immediately back to Down. This jump lines up with the big kick to the EX HEPI that causes the trip.