The problems we noted over the weekend with the ETM SUS (and sometimes SEI) systems tripping on lock loss (alog 11957) can maybe most accurately be characterized as a watchdog problem. The trips are caused by large drive transients after lock loss. It's hard to imagine that there's much we can do to prevent this from happening. Even if the DARM (CARM, etc.) control signals could be shut off immediately, the residual impulses would still produce large impulse response in the LOCK filters in the suspensions. We could try to shut off the drive signals in the SUS controllers, or hold the outputs at their current value, but that's a bit more difficult to implement.
In general, though, the watchdogs should probably just not be tripping on transients. If the watchdogs were a bit smarter and only tripped on sustained saturations or oscillations, this would likely not be an issue. I vote that we solve the problem in the watchdogs, but increasing the amount of time it takes before they trip.
I closely looked at one of saturday's trip on ETMX @ 04:44:40 UTC (May 18th 2014). The sequence was :
I will post some data tomorrow