J. Kissel for K. Kawabe

While Keita was working towards a power budget of the OMC DCPDs, after aligning light into the OMC the next step was to lock the OMC. Hindered by the H1OMC guardian's checks of many other not-yet-functional things, he went to lock the OMC by hand, thus for starters just yanking around the OMC PZT slider (Sitemap > OMC > OMC Controls > H1:OMC-PZT2_OFFSET), thinking that after Fil turned on the high voltage (on Jan 20 2022 LHO:61359) and OMC PZT driver chassis, the PZT would drive. Indeed, even the driver's HV DC and AC readbacks (H1:OMC-PZT2_MON_DC_OUTPUT and H1:OMC-PZT2_MON_AC_OUTPUT) made sense. But alas, no flashes of the OMC cavity.

Heading out to the floor, he found that the OMC PZT high voltage cable to the chamber was disconnected.

Our best guess is that this was disconnected during the Dec 13 2021 investigations of OMC PZT FRS Tickets -- see LHO:61034.

When Keita reconnected the cable and powered on the OMC -- with 0 [cts] requested out of the driver which the driver turns in to 50 [V] on the PZT (the same bad design as the HPDS PZT drivers... see discussion in LHO:60417, and rectified with some upgrade to the user interface see LHO:60549) -- it was roughly coincident with a trip of the HAM5 ISI CPS watchdog.

Upon recovery of the ISI, the team noticed the alignment had changed slightly... but still within the Irises on HAM6, and recoverable by the OMC ASC steering of OM3 and OMC.

Maybe an interesting connection to better understand the electrical interaction between HAM6 OMC PZT HV system and HAM5 ISI CPS system.