When a measuring system for a solar battery is operated and controlled by one execution program, the execution program is roughly divided into a program portion corresponding to measurement of a sunshine time in one day and a program portion corresponding to measurement for several to about 20 years. In this case, even a small error in part of the program may stop the entire measuring system. To prevent this, the program is divided into an execution program for acquiring data, an execution program for generating information to be displayed, on the basis of the acquired data, and an execution program for recording the acquired data in a recording medium. Interprocess communication is used to exchange data between the execution programs.