Last night, when I tried the oplev damping on the L2 stage (PUM) of ITMX, the damping loop did not improve the angular motion at all. This morning, Keita noticed that the OSEM read out at the L2 stage were all reading small numbers, indicating some electronics are not properly functioning or maybe disconnected. So I investigated this issue.

It was the coil driver which had been turned off for some reason -- the mechanical switch on its back panel was in the off position. So I switched it on. Now we can see some reasonable readout coming in to the digital system. We now should be able to use the oplev damping if necessary.