Wireless system for electrical networks testing based on MODBUS protocol

A wireless system able to test up to four remote terminal units (RTU) is presented. Each RTU establishes communication with a master unit (MU) through a radio modem, making use of the MODBUS protocol. Two kinds of RTUs were used. One of them consists of real electrical power meters, while the other one consist of a personal computer that works as an electrical power meter emulator. The master unit can be as far as 4 km distance from each RTU. The MU permanently runs a graphical software developed with LabVIEW/sup /spl reg//. This software asks for information from each RTU, saves this information in a file and generates a report. The information refers to the main three-phase electrical network variables, which are voltage, current, frequency, power factor, harmonic distortion and active, reactive and apparent power.