Reports 1-1 of 1 Clear search Modify search
AdV-DET (Commissioning)
gouaty - 23:09 Tuesday 30 November 2021 (54054) Print this report
SPRB drift control with 112 MHz signals

This afternoon, we tested the SPRB drift control using the B2_QD2_112 MHz error signals (which was implemented this morning - see entry 54043).

On Fig.1, the drift control was first engaged with the DC signals during the lock acquisition, then the 2f signals were engaged at CARM 0.

Fig.2 shows another example for which the drift control was using the 2f signals during the lock acquisition and then at CARM 0.

Both examples shows offsets between the 2f signals and the DC signals of the quadrant. The largest offset is in the vertical signal, which keeps increasing until the interferometer unlocks. One can observe that the trend of the vertical error signal is correlated with a trend on the bench TX position, which is now increasing (it was decreasing with the drift control based on the DC signals).

Since the drift control with the 112 MHz signals seems to work robustly we keep it like this for the time being.

Fig.3 shows the min/max of the quadrants RF channels (B4_QD1 and B4_QD2) during an example of lock. It can be seen that the B4_QD2 RF channels do not saturate any more (as expected thanks to the reduction of the VGA gain performed this morning). However a saturation is still visible on the the B4_QD1_DL channel (Fig.4).

Images attached to this report
Search Help
×

Warning

×