F. Clara, J. Figueroa, J. Kissel, M. Pirello
ECR E2400409 and E2500296 (IIET 35739 and 35706, respectively)
WP 12901
DWG D0902810-v12
DCN E2500341

Today we've gone forward with merging the sush2a and sush2b IO chassis, facilitated by upgrading those SUS's DAC cards to 32 CH, 28- bit DACs (D2200368). This entry covers the analog electronics and cabling that were impacted by the change, covering that all of the suspensions in, or soon to be in HAM1 and HAM2 -- MC1, MC3, PRM, PR3, IM1, IM2, IM3, IM4, RM1, RM2, PM1, JM1, and JM3.

We followed changes outlined in E2500341 which highlights the changes in the sush12 SUS electronics system drawing from D0902810-v11 to D0902810-v12. 
That required 
    - disconnecting all affected AI output cables in SUS-C3 and SUS-C4,
    - Removing the existing 6x 2x 8CH DAC AI chassis (D1000305), 
    - modifying them to become D2500353 1x 32CH AI chassis 
        . replacing the 2x 8CH AI rear panel with WD relays (D1000551) with 1x 32CH AI rear panel without WD relays (D2500097)
        . replacing the 2x 8CH back panel (https://dcc.ligo.org/LIGO-D1000552 with 1x 32CH back panel (D2400308)
    - re-installing, then
    - cabling everything up according to the D0902810-v12 version of the wiring diagram.

Here's the list of modified AI chassis serial numbers and assignment:
                                                     D1000305 > D2500353     D2500097
SUS Chain                     Rack / Position        Chassis S/N             Rear Board S/N          32CH DAC Card / IO Slot      Channels (Counting from 0)
MC1, MC3, PRM TOPs            SUS-C4 / U30           S1104370                S2501311                DAC0 / #2                     0-15
PRM, PR3 TOPs MC1 MID BOT     SUS-C4 / U29           S1104374                S2501315                DAC0 / #2                    16-31

MC3, PRM MID/BOT              SUS-C4 / U22           S1104375                S2501310                DAC1 / #4                     0-15
PR3 MID/BOT, RM1, RM2         SUS-C4 / U21           S1104378                S2501312                DAC1 / #4                    16-31

IM1, IM2, IM3, IM4            SUS-C4 / U10           S1104377                S2501314                DAC2 / #5                     0-15
PM1, JM1, and JM3             SUS-C4 /  U2           S1102760**              S2501313                DAC2 / #5                    16-31

** Technically, the (now) PM1, JM1, and JM3 AI chassis S1102760 was a 16-bit DAC AI chassis (D1101521) instead of a D1000305 at the start of today, and it didn't *need* the additional 16CH pass-through SCSI connection, but in the spirit of making everything the same, we elected to make it a full "new normal" D2500353 chassis.