After we got signals from the NF PSD, we started to check the signal. 

One problem we noticed is that what we thought should be the Y signal was actually 20X, so with the help of Babara, we changed the cables that connected to the ADC 275, now on the ADC, channel 4 is connected the cable 0 of the NF PSD, channel 5 connected the SUM and channel 6 connected the cable 1 from NF PSD. 

Then we measured again the sensing matrix with two sensors and two actuators.We sent 1V to M5 and 0.5V to M7. The measured snesing matrix are 

Then we invert this and use it as our diving matrix. 

We closed the loop, but start to observe a very large drift in the actuators voltage and the tranmitted power, in 20min the power could change about 3%.(pic) Depending on the gain difference between actuators, we start to see both increase and reduction of the transmission. 

We tried to set different gains and found an optimal combination listed below, this requires every DoF has its own filter

ACL_FILTER_SET        "GR_BPC2_M5_X_flt"        5    0.012        1    8
ACL_FILTER_POLES    "GR_BPC2_M5_X_flt"        0     0 
ACL_FILTER_POLES    "GR_BPC2_M5_X_flt"        1     1 

ACL_FILTER_SET        "GR_BPC2_M7_X_flt"        5    0.005        1    8
ACL_FILTER_POLES    "GR_BPC2_M7_X_flt"        0     0 
ACL_FILTER_POLES    "GR_BPC2_M7_X_flt"        1     1 

ACL_FILTER_SET        "GR_BPC2_M5_Y_flt"        5    0.018        1    8
ACL_FILTER_POLES    "GR_BPC2_M5_Y_flt"        0     0 
ACL_FILTER_POLES    "GR_BPC2_M5_Y_flt"        1     1 

ACL_FILTER_SET        "GR_BPC2_M7_Y_flt"        5    0.005        1    8
ACL_FILTER_POLES    "GR_BPC2_M7_Y_flt"        0     0 
ACL_FILTER_POLES    "GR_BPC2_M7_Y_flt"        1     1 

In order to understand how much the beam moves by the loop, we switched on the dithering llines around 21:01 UTC. We will check the perfomance of the loop tomorrow.

On the side from this work, we also tried to check the IR, we recovered the green and IR steering mirrors position when last time it was aligned (July 17th) and aligned the cavity on this position.But we could not see any beam arriving on either the EQB2 camera or the PD, it would be better to check if the beam arrives in EQB2 bench or not with the card. 

The set points of the green mirrors on July 17th are listed below:

M5 X 0.6 

M5 Y 3.78

M7 X -2.34

M7 Y 0.671

The set points of the IR mirrors are alreday written in the config file.