st.waitCacheChange(2000)
val=st.take()
fit_pos = val["x_fit_mean"], val["y_fit_mean"]
offset_offset = fit_pos[0] - marker_pos_offset[0], fit_pos[1] - marker_pos_offset[1]
offset_slope = fit_pos[0] - marker_pos_slope[0], fit_pos[1] - marker_pos_slope[1]
offset_all =offset_offset+offset_slope
set_return(offset_all)