Sudarshan, TJ, Sheila

Yesterday the ISS second loop caused 4 locklosses.  Times of the first three are 2015-08-17 22:28:26 21:52:13 and 20:54:05, plots are attached. 

The problem seems to be that the first loop diffracted power was large yesterday (13%, maybe a result of PMC misalignment? ).  The reference signal level was hard coded into the IMC guardian, which doesn't seem like a good idea since this does drift somewhat and we don't want to loose lock when it does. 

We have tried to edit the guardian so that iss_diffracted_power_target is now a dictionary, it gets set to the current value of the diffracted power before the second loop is closed.  If we're feeling brave and satisfied that we have recovered from our maintence day, we will try to engage it again.