This thesis starts with a description of the FreeRTOS operation system, followed by a short description of electricity meter by Iskraemeco. At the end, the implementation and analysis of the library for tracking the built-in software code of the electricity meter with the FreeRTOS operating system is presented. The library allows to turn on and off writing messages for each module to various possible outputs (file, screen, serial port). All settings can be changed during the operation of the meter. The library is intended for finding and eliminating errors in the software of the meter in the field, as well as outside it.