The two attached trend plots show the X & Y dofs of the ISI CPS for HAMs 2 & 3 for the past ~90 days.
Bottom line: I will reset the isolating position to the current free hanging position. Looking at the trends over the last few months while working on the IO, the locked positions for HAMs 2 & 3, X & Y have been ~40 to 50 um at worst and within a few um of the now free hanging positions. It seems this shift in X & Y would not be noticed by the beam path.
Detail:
| State | Free hanging um |
Locked position um |
||
| DOF | X | Y | X | Y |
| HAM2 | 15 | -66 | -20 to 0 | -55 to -35 |
| HAM3 | 10 | 2 | -5 to -1 | -2 to + 10 |
We'll revisit these numbers after pump down. Setting these servo to position to the free hanging position is an effort to make the isolating smoother and less likely to cause an isi trip. Additionally, when the platform does trip, the platform should move less making other systems (Sus) less likely to trip.
SDFs (safe and OBSERVE) updated and committed to svn:
hugh.radkins@opsws1:burtfiles 0$ svn st
M h1isiham3_OBSERVE.snap
M h1isiham2_safe.snap
M h1isiham3_safe.snap
M h1isiham2_OBSERVE.snap
hugh.radkins@opsws1:burtfiles 0$ svn commit -m "update cart bias targets"
Sending burtfiles/h1isiham2_OBSERVE.snap
Sending burtfiles/h1isiham2_safe.snap
Sending burtfiles/h1isiham3_OBSERVE.snap
Sending burtfiles/h1isiham3_safe.snap
Transmitting file data ....
Committed revision 16523.
hugh.radkins@opsws1:burtfiles 0$ pwd
/opt/rtcds/userapps/release/isi/h1/burtfiles
hugh.radkins@opsws1:burtfiles 0$