Relative positioning of telescope and building

One of the two pistons that the define the position of the telescope relative to the building in the azimuth direction has not been used until now was found to have a missing wire which was repaired. The two pistons give rather varied results depending on the position of the telescope. However, at low values which happen to be when the telescope is close to the limit switches in either direction on the building, both pistons show well defined and repeatable values. This is now used by the system to avoid ``building crashes'' (see below) to be able to get as close to the limit switches that would cut the power to the telescope before stopping the telescope. This also mostly removes the main `disadvantage of the new system that provide less time between the safety system cutting the building power and the telescope being stopped (now in a soft way as compared to the previous ``building crashes'').