aLIGO LHO Logbook

H1 CDS

david.barker@LIGO.ORG - posted 16:09, Tuesday 29 July 2025 - last comment - 16:43, Tuesday 29 July 2025(86086)

h1susex powered down for 3rd 18bit-DAC replacement

Elenna, Jeff, Richard, Jonathan, Oli, Ryan C, Dave:

We are replacing the 3rd 18bit-DAC in h1susex (cardnum=2). This DAC is exclusively used by h1sustmsx and could be causing lock-losses.

Drawing can be found in DCC D1301004, shown in attachment. DAC to be replaced shown circled.

h1susex is powered down, SWWD has been bypassed.

Images attached to this report

Comments related to this report

david.barker@LIGO.ORG - 16:14, Tuesday 29 July 2025 (86087)

Link

We briefly entertained the idea of upgrading this 18bit-DAC with a 20bit-DAC, but because it is interleaved between the existing 20bit-DACs the card numbers would change for h1susetmx and h1susetmxpi requiring those models to be changed too. So for expediency we are replacing 18bit with 18bit and no model/DAQ changes are needed.

erik.vonreis@LIGO.ORG - 16:43, Tuesday 29 July 2025 (86088)

Link

Replaced the third 18-bit DAC (18AO8 sn 101208-29) with another (18AO8 sn 110425-48). h1susex is back up and running.