Virgo Logbook

Reports 1-1 of 1

AdV-DET (Commissioning)

gouaty - 10:17 Tuesday 30 July 2024 (64810)

SDB1 angular control and OMC temperature control restored in vacuum

This morning, the gain of the OMC Peltier loop has been restored to its standard value in vacuum (50) and the OMC temperature control has been re-engaged at 7h43 utc.

We restore the SDB1 angular setpoints used in vacuum and close the SDB1 angular control loops at 7h51 utc.

Since the correction in TZ is quite high (6V) we act on the motorized counter weight to reduce it:

TZ: 9*-2000 = -18000 steps

TX: 5*-2000 = -10000 steps

We note that the correction in TY is -3.4 V, while it was around -1V before the vacuum break. Thus the TY torque has changed.

SDB2 position loops closed at 8h08 utc.

Comments to this report:

ruggi - 15:09 Tuesday 30 July 2024 (64817)

The large correction on SDB1 MAR TY has been removed performing a motorized rotation of MA suspending wire, at the level of the upper clamp (connection below F7). The performed action is 1400 steps CCW on the motor called MA.F7.U F7 top in SAT motor interface. The name is wrong: this is an old mistake in the short tower interfaces. The correct name should be MA.F7.D F7 down, but that name actually point to the vertical motion of F7.

The action had an effect also on TX and TZ MAR correction, luckily in the direction of reducing them. There was also a small displacement of the bench by a couple of microns. All those side effect are likely due to the fact that the electrical cables exert a strong action on the bench and any change in their position can modify the marionette position and balancing in all the d.o.f.s.

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