Following doors being hung on the HAM4 chamber earlier today Phase 3a DTT TF measurements have been taken this afternoon for SR2 (HSTS) suspension as follows:-  

- SR2 M1-M1 undamped results (2014-07-22_1200_H1SUSSR2_M1_ALL_TFs.pdf)

HAM4 ISI Status: ISI unlocked, no damping or isolation loops running.

SR2 alignment: No offset was applied during this measurement.

SR2 undamped measurements from above have been compared with other H1 HSTS suspensions at the same Phase of testing (allhstss_2014-07-22_Phase3a_H1SR2_UnDamp_ALL_ZOOMED_TFs.pdf). The plot key is as follows:-

Blue Trace = Model (hstsopt_metal)
Orange Trace = H1 SRM M1 (2014_07_21_1400), Phase 3a (in-chamber, doors hung) 
Magenta Trace = H1 SR2 M1 (2014−05−07_1083546862), Phase 3a (in-chamber, no doors)
Cyan Trace = H1 SR2 M1 (2014−07−22_1200), Phase 3a (in-chamber, doors hung)

Summary:

It can be seen that back on May 7th SR2 M1-M1 TFs looked good (magenta trace). However, subsequently, SR2 appears to have developed an issue with the M1 LF BOSEM channel (cyan trace). This was not evident in recent TFs taken during close-out activities since there is a window of opportunity to take P and V DOFs. We next need to further investigate the actuation chain (applying offsets, measuring coil resistances etc.) to determine if the fault resides in-chamber or with the electronics.   

All data, scripts and plots have been committed to the sus svn as of this entry.