In this paper work, we consider implementation of electronic control unit (ECU) for agricultural machineries. Software implementation is based on IsoAgLib library developed by OSB&IT Engineering Company. We modify IsoAgLib and upgrade it for our target system. The IsoAgLib is an object oriented C++ library that has the communication services and management systems according to the ISO 11783 standard. This library allows building ISOBUS compatible equipment without the protocols implementation contained in this standard. We focus on developing ECU of GPS sensor, ECU of light control and ECU of sprayer. Hardware implementations of ECUs are developed by using STM32F107 ARM 32-bit Cortex™-M3 CPU and CAN-bus receiver/ transceiver driver chip. Time managing of the system is implemented using time stamp messages between ECUs and virtual terminal.