In HAM-SAS no inertial control was

In HAM-SAS no inertial control was foreseen; just horizontal and vertical geophones for monitoring the isolation performance were mounted on top of the optical bench during the test campaign. In AEI-SAS, three monolithic horizontal low-frequency accelerometers and three vertical geophones sealed in vacuum cans are used to monitor and control the horizontal and vertical motion. The geophones are installed inside the AEI-SAS optical table underneath the breadboard. The monolithic accelerometers are much better positioned in the spring box, where the are insensitive to the optical table tilt.