Modbus + VOBO = a new revolution in wireless data grabs


Written by: John M. Greene

Volley Boast is pleased to announce that our VoBo GP-1 and HL-1 models are now fully enabled to bridge Modbus devices to LoRaWANs.

From the very beginning of our journey into LoRa and all things IIoT, we knew that we would need to be able to handle Modbus. For readers who might not be familiar with Modbus, it is a widely used communications protocol allowing a single controller to read multiple sensor readings in a single cycle or “poll.”

The Modbus Challenge

Modbus is optimal for wired, externally powered devices that put out a lot of data. The typical Modbus implementation allows for “polling” 125 data points in a single call. Therefore, it is effectively the “go to” for heavy industrial equipment applications.

Modbus adoption on wireless networks remains fairly limited due primarily to the significant amount of data transfer involved. In particular, those hoping to use batteries to take advantage of the latest in modern telecom technology have struggled to find an effective solution. The VoBo changes that and enables Modbus devices to be truly wireless.

Our Method for Managing Modbus Data

A primary objective of the LoRa protocol has always been to allow for the use of battery-powered sensors. It accomplishes this by using extremely small amounts of data. Furthermore, LoRa also implements “channel plans” that differ by country and utilizes “channel hopping” to restrict and otherwise manage data use to ensure compliance with the various country-specific telecoms regulations. Working within these constraints, VolleyBoast developed new methods for extracting and otherwise processing Modbus data with VoBos.

These new methods also required new tools. We have always gone to great lengths to provide customers with the ability to deploy and subsequently manage VoBos and the sensors and devices they control. This ability necessitates configuration solutions for both local, “offline” (ie, with a physical cable) situations as well as those when a VoBo has already been deployed remotely. While the new modbus functionality created integration challenges to this process, we abstracted much of the complexity away from the user and minimized the need for them to be “LoRa experts” to be able to set up and deploy a VoBo.

With VoBos, users can also recover and transmit stranded data from previously installed legacy Modbus RTU instrumentation. Such Modbus-enabled instrumentation is generally powered externally and, therefore, the VoBo’s D-cell battery is necessary only to power its onboard LoRa radio. This combination enables a truly wireless comms installation powered by a single battery that can last many, many years. This is the magic of LoRa.

Going wireless with Modbus is a challenge. We are confident in the solution we’ve created with the VoBo, though. Are you ready to cut the wires?