J. Kissel, F. Clara, E. von Ries, D. Barker, E. Dohman, O. Patane, R. Short

After fixing MEDM screens, I was able to validate that all expected drive signal channel assignments reach the expected DAC outputs for H1SUSITMY, H1SUSITMX, and H1SUSBS. 

As such, I restored the function of top mass damping loops, L2 to R0 tracking for the ITMs, and optical lever damping for the BS.

We've confirmed that alignment offsets have been restored.

With the SUS happily damping, I then restored the seismic isolation system, using the SEI guardians to bring HEPIs and ISIs back to FULLY_ISOLATED for the ITMs and FULLY_ISOLATED_NO_ST2_BOO for the BS.

Executive Summary of the last 24 hours of events regarding h1susb123 DAC card failure:
    - LHO:84500 h1susb123's Slot 4, DAC 2 -- an 18-bit DAC -- died and caused the front-end to crash, which eventually tripped all BSC1, BSC2, and BSC3 seismic systems via Software Watchdog (SWWD) 
    - LHO:84506 Having agreed that we should take the opportunity to enact ECR E1900216 (IIET:13232) and upgrade all the DAC cards in the chassis to 20-bit DACs -- we prepped the h1susb123 user and IOP models for the change 
    - LHO:84508 Erik and Fil replace all 18-bit DAC cards with 20-bit DAC cards, Dave compiles, installs, and restarts the h1susb123 front-end's models with the new code.
    - LHO:84509 With the models running, Ryan and I installed updates to the COILOUTF filters to account for the calibration change between 18 and 20 bit DACs.
    - LHO:84514 I cleaned up the MEDM interface for the SUS-ITMs and SUS-BS to ensure they accurately show signal flow from user model output to the DAC.
    - (this aLOG) Having validated signal flow, we restored the SEI and SUS systems to full nominal functionality.