Reports until 08:38, Tuesday 24 March 2026
H1 CDS
david.barker@LIGO.ORG - posted 08:38, Tuesday 24 March 2026 - last comment - 13:21, Tuesday 24 March 2026(89613)
Recovering SWWD and HWWD trips after Mon 21:45 PDT earthquake

Corey, Fil, Erik, Jonathan, Dave:

Last night's earthquake caused SWWD trips for ETMY, ITMY, ITMX. It also caused a HWWD trip of ITMY (BSC1) which was concerning.

We were able to untrip the SWWDs, but we kept ITMY DACKILLED while we work on its HWWD.

Jonathan went into the CER and pressed the RESET button on the ITMY HWWD chassis, this did not untrip the power to the ISI coil drivers. We tried a second time, again no restoration of power.

The front panel and the readback by h1susitmy both agree that the only red led is SEI-trip, the input conditions PD=osem-photodiode-rms and LED=osem-led-current are both GOOD, which should have permitted the reset.

But when the reset button was pressed, the PD led went RED and the unit did not reset the SEI trip.

Fil is heading out to reboot the unit and possibly replace with a spare if it is not working correcty.

Images attached to this report
Comments related to this report
david.barker@LIGO.ORG - 13:21, Tuesday 24 March 2026 (89624)

WP13115 to possibly prevent future HWWD trips by shortening time-to-trip of SWWD to 15 minutes.

david.barker@LIGO.ORG - 10:25, Tuesday 24 March 2026 (89618)

Fil got the ITMY HWWD to fully reset by keeping the "fault reset" button pressed for many seconds.

david.barker@LIGO.ORG - 13:14, Tuesday 24 March 2026 (89622)

Attached plot shows the suspension started recovery when the SWWD SUS tripped at 22:19:52 and 41 seconds later the HWWD tripped at 22:20:33

Images attached to this comment
david.barker@LIGO.ORG - 13:17, Tuesday 24 March 2026 (89623)

Summary of our 3 HWWD trips has been submitted to the DCC T2600092

As was done at the end station test masses, we need to reduce the time-to-trip for the SUS SWWD from 20 minutes to 15 minutes.