Tonight was our chance to work with PRMI.  

We had a look at the phasing of AS36, following the same procedure as we used with MICH bright the other day 20961.  (locked PRMI, aligned by hand, used OM1 +2 to align all the light onto one quadrant, maximize the Q signal. )

For AS A the results were satisfying,

• the phases needed to maximize I are similar for all 4 quadrants,
• the signal levels were all similar,
• once I re-engaged the centering the signals were still similar on all 4 quadrants. 
• Exicitng BS pitch (12 Hz 1000 cnts in Drivealign) and measureing a tranfer function gave a signal that has the correct sign for pitch in all 4 quadrants, exciting yaw gave the right sign for yaw in all 4 quadrants.  

For AS B the situation was also reasonable, but everything was a little less good (the phases are similar for all quadrants, but not quite the same, the signal levels varied more, and when exciting the BS the phases were almost right for PIT and YAW.   Overall this seems reasonable to use.  The resulting phases are in the attached screenshot, the new phases are the epics values, the old phases are the setpoints.  AS B quadrant 3 did not change, it is 63 degrees.  

I will revert these momentarily, but the next steps would be to set the matrix for AS A yaw back to something reasonable (the current set up doesn't use segments 1 and 2), set the phases to the values in the screenshots, lock DRMI, excite SRM and move the phase of all 4 quadrants on each WFS in common to minimize the SRM signal in the Q phase.  Since DRMI locking is frustrating tonight with the SR3 glitches this will have to wait.