After the install of the new long range RFM, Dave and I have worked on adding channels and code to calculate common mode ground motion, to eventually use for improving earthquake lock robustness. Right now both endstation ISI's are sharing their ground beamline supersensor (gnd sts - brs), ground Z, ETM suspoint length and St1 beamline CPS. The first two channels are needed for the common mode calculations, the suspoint is used for the OAF suspoint cavity length calculations. I don't know what the CPS is used for, but I kept it in the list of channels being shared. Previously all 4 of these channels were shared via muxing through the endstation PEM models, but only the suspoint channel was being used for anything. I've now added some code to the OAF to take the corner and endstation ground seismometers and calculate common mode ground velocities (i.e (ex_z+ey_z +cs_z)/3= site-wide common mode z ground motion). The plan is to eventually take these cm signals and subtract them from the ISI sensor correction and only isolate the platforms from the local differential motion, but that will require more invasive ISI & HEPI model changes. Attached screen shot shows the section I added to h1oaf. I also added 3 256hz dq channels for the cm x/y/z outputs. After Dave restarts the models I'll throw together an MEDM for the filter banks. The plan for now is to just figure out how to get the common mode calculations right and get data to try some offline subtractions.