[en] The paper gives a survey of the data processing in an area monitoring system at a small research reactor. Eighteen instruments (ionisation chambers, Geiger Mueller counters, and scintillation counters as well as neutron monitors) are installed in the reactor hall and in some other parts of the institute's building which produce analog and digital signals at the central unit in the control room. If a preset alarm level is reached, optical and acoustical signals are triggered. A microprocessor controlled data logging system as a back-up system compares the analog signals with preset programmed alarm levels and prints the relevant data when certain criteria are fulfilled. For documentation the system scans the radiation levels continuously and prints a protocol several times a day which is available for reactor responsible persons and authorities. (author)