Characterization of a new PLC modem for an industrial application

The motor speed control is a typical industrial application where an extra cable is used in order to transmit control information´s from the motor to the controller. This cable is used for data transmission such as rotor speed, rotor position, temperature and vibrations. One cable is used per motor. In some cases, it might have length exceeding few hundred meters, which can be problematic in terms of price and overall dimension. The aim of our study is to develop an industrial power line communication (PLC) modem allowing transmission through the feeder cable based on the PLC technology without using extra cabling. PLC technology exists already in the market but its reliability has only been demonstrated in domestic application through the electrical network 230 V/50 Hz. The power signal through the feeder cable is the Pulse Width modulation (PWM) signal which is a signal of higher frequency and higher amplitude than in domestic network and it can affect badly on communication. According to this, this paper will underline the reason of non communication of the PLC technology in this situation and the way to overcome it. We will define many characteristics of the PLC modem that will allow us to couple the information to the three phase cable and to communicate safely in order to ensure the controllability of the motor.