[Sheila, Camilla, Jenne]

We've been having several locklosses during Engage_ASC_for_full_IFO lately, and it seems like it might be because the PRM is moving too far too fast.  Recall that the PRM is being controlled by the ADS system, and that is engaged for the PRM during this state, along with a host of other ASC loops.

We have turned on the ADS soft limiters, to limit the inputs to an absolute value of 10 (when the dither line amplitudes were 1600). Also, the engage_ASC_for_full_IFO state was not doing any convergence checking on the PRM loop, so we have implemented that.  Since the smooth limiters are now on, we have also changed the dither_convergence_checker to look just before the input limiter.

We've had 1.5 lock acquisitions with these limiters, and so far it seems good.  The first time around we lost lock during increase power after having survived the ASC engagement, but I highly suspect that was due to me increasing the limits without any ramping, in an effort to speed up the loops (I had at first been using a much smaller limit of 3).  Our second lock has gone quite smoothly. 

Right now, the input limiters are being left on with the limit value of 10, however the dither line amplitudes (and so the input values) are decreased by a factor of 1600/30 (from 1600 to 30 counts), so we're basically never going to hit those limits.  If we feel that we need to keep the limits in play, then we should reduce the limit values also by a factor of 1600/30.

Also, these seem not to be monitored in SDF, so we should consider moving them to being monitored, but since we're already in Observe I'll push that to another day.