Jim, Sebastien

We've been seeing some weird issues all day on BSC-ISI ETMX.

After restarting the models on all the BSC-ISI platforms this morning (see post here), we realized that the horizontal (X, Y, RZ) lvl3 controllers on ST1 were all equal to an empty zpk with a gain of zero

zpk([],[],0.000000000000,"n")

First mystery.

We successfully reinstalled those filters using the seismic scripts to do so (autoquack function).

Second mystery: when we turned the controllers lvl3 on, we noticed a huge drive on the horizontal DOFs, especially on ST1-H3 (~15000 counts according to the overview MEDM screen).

After some investigation, we can see some high frequency features in the closed cloop power spectra, especially at 718.875Hz (see plot attached).

This features show up on all the axis, especially in X (which explains the huge drive on H3), and only with the lvl3 controllers (looking at these controllers in foton, they actually look fine...).

My guess so far is that there is something wrong with our foton file. Arnaud is taking some measurement right now, so I'll continue the investigation later.

Lvl2 controllers are actually engaged on ST1 and ST2 (with Tcrappy blend filters)