A new alarm system which provides a qualitative description of process data trends is presented in this paper. This description is based on a method of marking process data with significant words. The objectives of this system are (1) automatically to recognize a punctuation on a process instead of plant operators, and (2) to develop a fundamental technique for data trends monitoring systems by using a qualitative description. Recently, this system was used to catch a fluctuation on a real process before it became dangerous situation. Finally, more applications of using a qualitative description for the plant operators which will be developed in the near future, and the method of detecting a reasonable fluctuations are presented.