In this paper we present a national project located in the area of computer aided testing and certifying (CATC) of physical devices. The objective of this project is to develop an Information System that supports the various activities of different user groups in a German federal institute of weights and measures. We decided to use formal methods right from the beginning of the project. Our approach is based on the formal object oriented specification language \sc Troll. Starting point of the development is an abstract model of the organization which will serve later on as a formal basis for implementation. We present parts of this specification and its relations with the underlying formal semantics. The experiences we made so far are rather positive and we expect further effects in the future.