Virgo Logbook

AdV-SAT (Suspension control upgrade)

Boschi, Piendibene, Ruggi - 16:09 Friday 25 October 2024 (65400)

NE Issues after Fan Unit Replacement

On the afternoon of October 23rd we replaced a fan unit of Sa_NE: one the three fans was spinning at slow speed generating a strong acoustic noise that was noticed by the ENV team. Unfortunately after the crate reboot required by the replacement, simultaneous periodic glitches (every 20-30 minutes) appeared on both horizontal and vertical accelerometers. The issue was solved yesterday by replacing the MCH (serial #110334-3224 was replaced with serial #110335-12922) and removing vertical accelerometer board (serial #41065) that was not transmitting properly on RapidiO bus. During one of the next maintenance windows we will try to regenerate the glitches re-inserting the board in the crate. In case we succeed, we will replace both horizontal and vertical LVDT boards with an LVDT and p4 Coil Driver set.

Comments to this report:

Boschi - 16:13 Tuesday 05 November 2024 (65468)

This morning I re-installed vertical accelerometer board (serial #41065) in a different slot (#6 instead of #4). Unfortunately the periodic glitches reappeared. Board has been removed and will need to be replaced.

Boschi, Montanari - 12:33 Thursday 14 November 2024 (65531)

On Monday 11th we replaced the distribution box connected to NE accelerometers in order to exclude it from the possible sources of the glitches. Unfortunately the test was unsuccessful: the glitches reappeared after a few hours. In the next days we will replace the boards.

Boschi, Di Pilla, Gkaitatzis, Montanari, Piendibene, Ruggi - 11:46 Tuesday 19 November 2024 (65564)

On November 18th accelerometer DSP boards (serial #31015, #41065) have been replaced with an LVDT and a DIFF board (serial #43170, #45275). The relative distribution box has to be replaced as well with a v2. For each sensor, demodulation phases has been set, transfer functions measured and controllers re-designed. Code has been changed in order to allow automatic TF measurements. DSPServer configuration files has to be updated due to the hardware changes. New gains for horizontal and vertical inertial damping has been estimated as well. During the night both IP loops has been kept closed and no glitches have been reported.