VFD Integration Over MQTT

Project Overview:

  • In a Data Center there were about 4-5 VFDs (Variable Frequency Drive) and they needed to be controlled and monitored using MQTT protocol.

Initial Situation:

  • VFDs were looped on RS485 Port and provided output in Modbus RTU (RS485) Protocol.
  • The monitoring and control system that was cloud based only supported MQTT protocol.

Customer Requirement:

  • Customer wanted to monitor and control VFDs data like Voltage, Current and Frequency from cloud.
  • The VFDs work on Modbus RTU Protocol and Cloud API understands MQTT. Therefore, a direct exchange of data between them was not possible.

Solution Provided:

  • ProtoConvert suggested a Gateway in which we can get the data from all the VFDs on RTU and post it on MQTT Broker.

Note: Client had purchased MQTT Broker Subscription

  • The customer’s monitoring system subscribed Parameter tags on MQTT Broker.
  • With the help of ProtoConvert Gateway, customer could monitor and control Data Center’s VFD data via MQTT Broker.
  • The customer’s monitoring system could send back commands to update the Parameters on MQTT Broker.
  • ProtoConvert Gateway had subscribed to these Parameter Values and on change relayed the commands on Modbus RTU enabled VFDs.


  • Thus using the ProtoConvert Modbus RTU / MQTT gateway the integration of modbus RTU based VFDs with a cloud based monitoring system (that supported MQTT) was achieved.


  • VFD (Variable Frequency Drive),
  • MQTT Protocol,
  • MQTT Broker,
  • Data Center,
  • API (Application Program Interface),
  • Voltage,
  • Current,
  • Frequency,
  • Modbus RTU Protocol,
  • Parameter Tags,
  • Publisher,
  • Subscriber