Sub-metering of machinery in mechanical engineering

The project implemented sub-metering at a mechanical engineering plant specialising in high-precision products, with the aim of gaining a detailed overview of electricity consumption. In the first phase, we focused on the machinery that mattered most in terms of energy draw and technical importance.

Metering was achieved by networking the metering devices over the Modbus RTU protocol, in a hybrid network topology: each switchboard housed a Modbus RTU to TCP converter, to which the individual meters were connected in a line topology. We then connected all the converters centrally to the relevant switch in a separate subnet (VLAN) to ensure reliable, isolated communication.

As the industrial ‘edge’ solution, we used a Revolution Pi, which collects and aggregates the data. It was given its own VLAN with internet access, which makes remote management possible. We equipped the Revolution Pi with a backup power supply (UPS) with a battery to eliminate the risk of metering dropping out during a power cut.

Together with our partner company, which led the project, we developed a visualisation that displayed the measured data in real time, analysed consumption and raised alarms for hazardous states. A system for recognising the state of each machine was also integrated at the client’s site, so it is possible to track whether machines are in full production, idle or at standstill, giving a complete view of how production capacity is used.

We installed 79 metering devices, and the total number of electrical components installed reached 109, ensuring detailed monitoring of all relevant parts of production. The result is a reliable and detailed system that helps reduce energy costs, optimise production processes and support better maintenance management.

Two further phases are now being prepared, which plan to extend metering to further machinery and add other utilities (water and gas) to the system, together with ambient temperature measurement, to give an even more complete overview of operating conditions in the plant.