J. Kissel, T. Shaffer

Last Friday, I told TJ to flip 2 of the 4 H1SUSZM1 magnets (UR and LR) because I'd found that I needed to flip the signs of the corresponding COILOUTF bank to make the transfer functions look clean (see LHO aLOG 40808 and subsequent comments). In doing so, I'd insisted that "sadly, all HTTSs (except for RM2) have their magnets oriented exactly opposite to their documentation" (the controls arrangment poster, E1400316), and concluded that -- instead of fixing every other HTTS -- we convert ZM1 to the "wrong" convention such that they're at least all the same. This statement was based on the sign of the required damping loop gain, assuming all other digital signs were correct.

This morning, he flipped magnets according to what I've insisted, so I re-took transfer functions. They revealed the phase remained zero at DC, instead of being -180 like every other HTTS, implying that I understand the magnet polarities exactly wrong.

Upon closer inspection and a review of all signs with TJ, we've identified the real problem is because I have been blindly obeying the sign convention table in T1200015 for "BOSEM 4 OSEM Stage" when it comes to the COILOUTF gains. However, this table was created for the QUAD's UIM stage (the only other 4 OSEM stage in the IFO that has BOSEMs). 
The QUAD's UIM, BOSEM 4 OSEM magnet orientation, as shown in E1000617, is exactly opposite that of the HTTS.
#facepalm.

So, after apologizing profusely to TJ, I've asked him to now flip both sides flag/magnets to be exactly as is shown in the HTTS controls arrangement poster (again, E1400316), namely
    UL        UR
    N          S

    
    S          N
    LL        LR
and now *I* need to change all HTTS's COILOUTF gains: 
          Are Now   Should Be
    UL       -1        +1
    LL       +1        -1
    UR       +1        -1
    LR       -1        +1
so that the BOSEM coils obey the correct push-pull force table at the top of T1200015, damping loop gains can be an easily understood -1.

I'll sure to check with LLO to make sure they update, if needed, and then make a new version of T1200015 that specifies the difference between a QUAD and an HTTS BOSEM 4 OSEM stage.