Case study for protocol conversion from Modbus RTU to BACnet IP along with data logging

Project overview:

One of a very well know building has 200 energy meters located on different floors and building management authority wants to get data of all the energy meters on central Building Management System (BMS). At the same time they want a backup of data locally.

Initial Situation:

 The building has 10 floors and 20 energy meters on each floor. Each floor has 2 RS485 loops of roughly 10 meters each. The energy meters work on Modbus RTU on RS 485. Each floor has ethernet connectivity. The BMS is installed on a server in the basement. Hence the RS485 loops terminate on the floors and the data communication to the BMS is proposed to be over Ethernet. The BMS support BACnet IP protocol. Also the facility manager requires that data logs be kept per floor for energy and other readings on the meters. Hence the additional requirement of data logging and report generation per floor.

Customer requirement:

To manage the premises, authority wants to monitor and analyze all the energy meters data like power, current, voltage etc. from their BMS. The energy meters support Modbus RTU protocol but the BMS is o BACnet Ip protocol. There is an additional requirement that the facility manager wants the ability to generate floor wise reports as a back up. Hence there should be local data logger per floor that keeps a logs data from the meters for local report generation. Summary of the requirement:

-Protocol conversion from Modbus to BACnet IP so that the BMS can monitor the energy meters

-Data logging at the floor level so that reports can be generated at the floor and serve as data back up

Solution provided:

ProtoConvert analyzed the situation at hand and considering the two fold requirement of protocol conversion coupled with data logging recommend the ProtoConvert Modbus RTU data logger model PG-WS-100-103-DL. The ProtoConvert gateway made the integration almost plug and play. With extremely minimal configuration (just a couple of clicks) it was possible to quickly integrate the Energy meters with the BMS. Additionally this model provides on board data logging and a simple web dashboard for monitoring values. It is possible to generate reports using the web user interface. The reports for historical values can be downloaded or emailed. Thus all the customer’s requirements were met. Finally, ProtoConvert team submitted a complete site report and discovered all the Energy meter on BACnet IP using a 3rd party BACnet discovery software. ProtoConvert also helped the BMS team with questions and brining the Energy meter data into the BMS using our converter.

Modbus RTU to BACnet IP Converter


This converter has been working on the site since long time now and have proven to be extremely efficient and reliable. Also, the customer and the site integrators have been extremely happy with the professional and timely services provided by the ProtoConvert team.

Our Modbus RTU to BACnet IP converter cum data logger has 1 or 2 -RS485 ports (depending on model selected) and 1 Ethernet port. Using the RS485 ports you can connect  RS485 trunk/s with our converter and in each trunk,  we can connect up to 31 devices using daisy chaining. The ethernet port can be used to connect to the BMS. The datalogging feature is extremely helpful in case of:

  • Remote monitoring software which does not support logging features.
  • Data back up in  case of Network issues/failures
  • Back up for BMS in case of any Power failure or shutdown of BMS server