Virgo Logbook

AdV-COM (AdV commissioning (1st part) )

bersanetti, mantovani, masserot, gouaty, was, mours - 22:31 Wednesday 19 September 2018 (42737)

ITF Recovery

Today the work on the recovery of the ITF continued; the main points are:

still no luck with the boost filter for the SSFS; a number of tests has been done (including reverting to an older, more tested configuration for the SSFS and a check on the MC DSP card) but we observed no change at all in the behaviour, so the origin of the problem is still not clear (entry 42736 may trigger some investigation on the ramps for the SSFS);
some problems occurred after the upgrade of the mezzanines' firmware:
- B1_PD2 is not usable at the moment, its configuration will be checked;
- most probably related to this, the logic of the slow shutter is not completely working as expected, but this is not a problem right now as the shutter is closed anyway, and it will be needed only after LOW_NOISE_1;
later, it was not possible to get to dark fringe anymore: during the last transition, still well before the maximum circulating power we always reach, either the fast shutter closes (cutting the B1p beam, Figure 1) or the B7_PD2 one does (Figure 2).

Images attached to this report

Comments to this report:

mwas - 8:04 Thursday 20 September 2018 (42740)

Figure 1:
The fast shutter closing is due to the B1 PD2 ADC communication problem that mixes samples from B1 PD2 and B5 PD1/PD2.
This creates artificial flashes on B1 PD2 that trigger the fast shutter.

Figure 2:
B7_PD2 is systematically closing the shutter at 10mA of current draw. The configuration file correctly states that it should be closing at 50mA for B7_PD2 and at 10mA for B7_PD1. Probably the two have been mixed by PD firmware update.

Images attached to this comment

letendre, masserot, mours - 14:12 Thursday 20 September 2018 (42743)

For the B7_PD2 the threshold was set to 10mA for a trial and we forgot to restored it to 50mA, is was done 2018-09-20-07h19m26.

Note that a reload Config is not enough to restore the threshold, today one need to reconfigure the mezzanine

For the B5_PD{1,2} and the B1_PD1 DC and Audio signal, there was some trouble with the Service mezzanine SN22 (SDB2_MezzPD1) while it was running with the firmware v3r1.

Restoring the previous firmware v3r0 allows to have the SDB2_MezzPD1 running correctly .We left the SDB2_MezzPD1 with this firmware (v3r0)