We've never made this official and there is always some evolution of things but we should get something in writing; so, here goes.
0) Chamber is under vacuum. 0.1) Things are vented, chamber is opened.
1) Lock the ISI (before anything happens to the platform), see attached from D071450 (which has lots more detail of the assembly):
a) Keep things quiet, don't disturb Stage1 (the suspended platform)
b) Lock the lockers turning them counter-clockwise; Squirting Isopropyl onto the locker sleeve is permissible but should not be needed.
i) always lock A B C & D in order for repeatability
ii) Locker letters are embossed on Stage0 of ISI, but not HAM6 (it's the same as HAM5)
iii) I have part of a locker in my office if you want to see one
2) Sit back, wait for others to do their thing and alter the table balance.
3) Rebalance the Platform. Display ...CART_BIAS.adl available from ISI CHAMBER OVERVIEW(2nd attachment)
3.1) Record the current, locked cartesian position of Z, RX & RY from the ISI Cart Bias medm.
a) Record to micron precision; screen displays to nanos
b) Load these as Requested Setpoints to get residual calculation
c) Residuals should now be a few microns at worst
3.2) Unlock the ISI, with payload change, may be difficult: lift, push, pull
as needed to ease, use Isopropyl if necessary:
a) Not critical but usually easier to reverse locking order--D C B then A
b) Residual now tells where things need correction
c) Medm graphic indicates Add, Remove, or Move Mass to & from
3.3) Change mass as required
a) our smallest mass is 50g
b) this will move the Z position a few um
c) this will swing the add/remove location more than you'd think
d) If you get the residuals to less than 5 micros, great, go to the next step
e) Given tradeoffs, leave Z high (buoyancy) get tilts close
4) Re-rebalance the ISI
4.1) Carefully relock the ISI as above
a) Record the positions
b) Are they much different from above step 3.1,more than a few micros?
c) If not different, pretty much done
d) If the the position is different, start over beginning with Step 3
5) Confirm locking and unlocking the ISI does not shift the tilts more than a few urads.
6) Runs some TFs to insure things are not rubbing badly or shorting.
