Differently designed measuring systems exist of which most contain a central signal processing unit and a number of electrical measuring components, and in which the measured values furnished by the measuring components are optically transmitted over optical wave guides. The aim of the invention is to provide a measuring system of this type, which has low power consumption and enables a reliable optical data transmission. To this end, an optical loop is provided between a central measuring unit (MG) and a sensor head (SK). Microprocessors (MP1, MP2), which are situated inside the central measuring unit (MG) and inside the sensor head (SK), carry out transmitting, measuring and monitoring tasks as a distributed controller with bi-directional data communication. A frame synchronization signal serves both for supplying power as well as for deriving a clock signal for block-oriented data transmission. A data communication is carried out for conducting a parameterization and/or programming between the central measuring unit (MG) and the sensor head (SK), and a pre-preprocessing of the measured values is carried out in the sensor head (SK), particularly a measured value correction and/or a range switching and/or a reprogramming of the filtering characteristics and/or an automatic compensation are/is carried out in the sensor head (SK).