Research Of The Aircraft Electrical Loads Computer Monitoring System Based On PLC

Electric Load Manage Center (ELMC) is an important component of AdvancedAircraft Power System (AAPS).Its performance dose a lot with the rationality ofpower distribution. The working process is: Receiving the layout command and therequest of the loads from the electrical system processor (PSP),combined with thecurrent state of the loads，ELMC completes the transform of the bus bar and the load’son-off controlling by the switching of the relay and solid state power controller (SSPC)on-off control,thus ensuring t the electrical supply to the load and improving powerutilization.There is a analysis in the functionality and performance of the advanced aircraftpower supply system’s Electric Load Manage Center (ELMC)， and a in-depthunderstanding of the structure and function of the aircraft’s electrical system. On thisbasis, the design and research of aircraft electrical load monitoring system begins.Aircraft electrical load monitoring system consists of two parts of host computer andnext-bit machine. Upper and lower bit machine use MPI to communicate with eachother. the next-bit machine design which is based on a Siemens PLC as the corehardware includes hardware selection,I/O port address configuration and eachmodule’s circuit design; The host computer generates a configuration human machineinterface with the Siemens configuration software WinCC.The system uses theSiemens PLC-300/400programming software STEP7and selects LAD as theprogramming language.The system simulates loads control in three flight statuses. Computer monitoringsystem shows how to comply the SSPC on-off control, the switch of the relays and theflight state transitions when the power generator is out of work, ensureing the safetyof aircraft flight.