Gateway OPC UA/Modbus applied to an energy recovery system identification

In this paper, a gateway OPC unified architecture (UA)/Modbus that runs on a Raspberry Pi 2 is presented. This piece of software allows using a PLC or other low-cost hardware in applications that were banned for this type of devices. In this way, the possibilities for instrumentation and control applications are expanded. As an application tool, data acquisition by means of the OPC UA/Modbus gateway, in this work, is used in the identification of an energy recovery system. The energy system consist in using a centrifugal pump in a twofold way. In the first one, the pump is used as a device controlling the water distribution pressure, and, in second place, the asynchronous motors is used as a generator which gives back electrical energy to the grid.