Division

A recess in the sphere shall allow for mounting one triaxial or three uniaxial accelerometers within ±10 mm seismic mass location tolerance from the centre of the sphere for the measurement axis, and ±1 mm seismic mass location tolerance from the centre of the sphere for the perpendicular direction to the measurement axis. The accelerometers shall be positioned in accordance with points 4.4.1 and 4.4.2.