sebastien.biscans@LIGO.ORG - posted 15:12, Thursday 23 January 2014 - last comment - 17:21, Thursday 23 January 2014(9503)
HEPI-ITMX position loops
Hugh, Sebastien
Position loops (UUG 5Hz) have been installed on HEPI-ITMX.
The design of those loops can be find in the SVN at:
/ligo/svncommon/SeiSVN/seismic/HEPI/H1/ITMX/Scripts/Control_Scripts/Version_5/GET_H1_ITMX_Controller.m
The function GET_H1_ITMX_Controller stores the zpk filters into a structure called FILTER_OUTPUT. This structure is used by the HEPI scripts steps 6&7 to generate the plots and saved the filters into the good format.
Sebastian and I looked at trends back during the day to set the Target positions for HEPI. We left the Pringle modes out of the loop for a while because they were generating large drives to the actuators. After a couple hours we saw the trends of the pringles not going anywhere fast so we set those targets and engaged those loops.
When I looked at longer term trends to make this log I see that the HEPI Location values were zero until Hugo and I worked on the position loops on the 16th and the input matrices were populated. The trends look very flat/stable until ~8pm 21 Jan. The ISC crew reports suddenly experiencing a sudden misalignment. They traced it to ITMx HEPI. Some confusion about whether or not they attempted to engage the uncommissioned HEPI loops but the point is, HEPI moved and stayed. They realigned the SUS and continued. So HEPI will stay here.
Attached is the current Cart_Bias for the Target positions. If you see the HP or VP numbers far from the Targets, know that these are AC coupled.