This afternoon, I tried to understand how to use the PSD to control the SQB1 bench (this loop controls TX and TY).
I enabled the bench loop with PSD and adjusted the gain of the loop up to a point where I could see the loop acting, I did that with the GR pointing loop off.
Then I injected white noise (up to 1 Hz) to the PSD error signals for about 1h30 between 15:50 UTC and 17:20 UTC aiming at measuring the transfer function of the loop.
Then I opened the PSD bench loop, close the GR pointing loop again.
Finally I opened the GR pointing loop again and closed the PSD bench loop around 18:23 UTC.
I will leave the system like this for the night (monitoring it to see if it is not going nuts).
I'll try to come up with some analysis later.