in this study, a new dsPIC microcontroller based PLC design for requirements of data acquisition, signal processing and control applications has been discussed. The aim of the study was to realize of today's automation applications with a more economic, convenient, and functional device other than PLC applications. This device is a general purpose product available in ali areas. it is used to determine the city power grid harmonics. The circuit schema of the device is drawn in Multisim environment. The design of the printed circuit board is implemented in Ultiboard. The Microchip IDE is used for writing the codes and programming the MCU. The C30 compiler is used for compiling the codes which is distributed free of charge by Microchip. To evaluate the performance of the product, the harmonics in the electricity netvvork are tested. The operating time of the two main functions which are used in the FFT algorithm that was used for determining those harmonics were observed and results were expressed visually. Further development that could be done, by other researchers, in the future, is also discussed in the final chapter.