I took some quick measurements of the ETMX ISI in DTT tonight using excitations both at stage 1 and in HEPI. I turned them both off using the guardian for these measurements. I reset them back to isolated before leaving.

I plan to finish these measurements tomorrow or later in the week, so not much to say about results yet. The idea is to check Zach Patrick's BSC-ISI N4SID matlab model, in ...SeiSVN/seismic/BSC-ISI/Common/BSC_ISI_Model/N4SID_Model. The model does not include ground (HEPI) displacement inputs. It is possible the responses from the stage 1 actuator inputs will have the same shape, just scaled differently. So the measurements are to check whether this is a worthy assumption. Thus, I am measureing stage 1 to stage 1, and then HEPI to stage 1. If the shapes match, then awesome. If not, we'll need to do more work to complete a BSC-ISI model.