After several false starts the new auto-centering software is finally ready to go. The attached screen shot shows the new medm screens. The screen to the left is the main servo screen. It shows the DC readouts of the WFSs leading to pitch and yaw matrices which then are fed into the new integrator filter modules (IFM). The screen to the right shows the new trigger logic. The auto centering is engaged automatically, when there is enough light on the WFSs, when the IFMs are in auto mode and when the main enable switch is on. This SUM thresholds are adjusted on the trigger screen. Whenever the SUM trigger is off, the corresponding integrators are bled off. This ensures that they come back to a good state, if they get completely out of alignment. The later is sometimes introduced by a misalignment of the ETM.
The RMS thresholds are used to decide, if the PZT servos have settled. The logical AND of all triggers is sent to the WFS servos as an additional trigger to engaged the alignment servos.
The attached pdf shows a typical transfer function of an auto-centering servo with a ugf of 10 Hz.
Elli, Daniel
We noticed that PZT2 used for centering WFS_B in end X was out of alignment range. We were tapping at different mounts to see if something was flaky. Indeed, we found that the PZT mirror was not very well attached. This is a press-fit mount and had too much slack. We jammed in a piece of plastic material and realigned the path.