The Babel Buster BB2-3060 Modbus TCP to BACnet gateway allows Modbus TCP devices to communicate with BACnet MS/TP devices. Modbus registers are accessible as BACnet objects and BACnet objects may be read or written as Modbus registers. The Modbus TCP to BACnet gateway acts as a protocol translator between the two networks.

The Modbus TCP to BACnet gateway operates as Modbus TCP client and server at the same time. As a client, the Babel Buster BB2-3060 will continuously poll Modbus TCP devices according to the register list you provide, and save the register data in BACnet objects which can be accessed by other BACnet devices. Data will flow in either direction, from Modbus to BACnet, or vice versa.

BB2-3060 Modbus TCP to BACnet Gateway Functionality

The Babel Buster BB2-3060 can also be configured to continuously poll BACnet objects in other devices, and save that data in local objects that can be accessed as Modbus registers by other Modbus TCP clients.

Feature Highlights
• Connect Modbus TCP Devices to BACnet MS/TP Network
• Connect BACnet MS/TP Devices to a Modbus TCP Network
• Subscribe to COV on Changes from Modbus or BACnet
• Up to 300 BACnet Objects and 300 Modbus Registers
• BACnet Input, Value, Output objects for Analog, Binary, Multistate
• Up to 300 Modbus Registers as Coil, Discrete, Input, Holding
• MS/TP baud rates: 9600, 19200, 38400, 76800
• FCC, CE Mark, UL 916 Listed
• Software Included, No Drivers to Buy

BB2-3060 BACnet MS/TP to Modbus TCP Gateway

Babel Buster BB2-3060 BACnet MS/TP to Modbus TCP Gateway

This model is now out of stock and out of production. We have a newer gateway that replaces the BB2-3060 with higher performance at lower cost:

BB3-7301 BACnet Router plus Modbus TCP

Control Solutions’ Babel Buster® BB2-3060 is a BACnet MS/TP client/server device that functions as a Modbus TCP client/server. A large number of BACnet objects gives you flexibility in mapping Modbus registers to any combination of BACnet objects. Packed Modbus registers may be parsed to multiple BACnet objects when reading. Multiple BACnet objects may be packed into a single Modbus register when writing. All standard Modbus register types are supported.

Input objects will poll their assigned Modbus register at the interval you specify, and provide the Modbus data as the Present Value when read. Commandable Output objects are used to write Modbus registers, and will update the Modbus device each time BACnet is updated. The BB2-3060 supports up to 300 non-commandable objects, or up to 135 commandable objects, or a mix in between.

Value objects will poll their assigned Modbus register at the interval you specify. The content of the Modbus register will be given as the Present Value of the BACnet object when read. The Modbus register is written each time the BACnet Value object is written. The Value object corresponds to the Modbus Holding register.

The BB2-3060 is most often used as a Modbus TCP client (master), but it can operate as a Modbus TCP server (slave) while MS/TP operates as a client (master). This makes it possible to put MS/TP devices on a Modbus TCP network (but does still require an understanding of BACnet). MS/TP data in remote devices is queried and saved locally. The local data may then be accessed by another Modbus master.

The BB2-3060 configuration tool connects to the MS/TP network using the MTX002 MS/TP to USB adapter (if not using a BACnet IP router). This intelligent adapter plugs into your PC's USB port, and offloads the MS/TP token passing from the PC to make it more reliable. The MTX002 allows you to connect your PC to an MS/TP network running at 76800 baud, something not possible with a generic RS485 port adapter.

The MTX002 functions as an MS/TP device itself. The combination of the MTX002 and configuration tool running on your PC will appear on the network as a discoverable BACnet device. The diagnostic pages in the configuration tool can be used to read and write any objects in any MS/TP device on the network. The configuration pages provide templates for reading and writing the multiple properties per BACnet object that define its Modbus mapping. All configuration parameters exist as properties of BACnet objects which are accessible to any BACnet client. The Control Solutions configuration tool simpy provides a user friendly template for accessing those properties.

BACnet to Modbus Gateway Configuration Tool

The BACnet Gateway Configuration Tool is the most user friendly BACnet gateway configuration tool to date. Connect the gateway to your laptop via a USB to MS/TP adapter (MTX002) or via a BACnet IP router.

Import Modbus register lists formatted as CSV files. Create your register list using any standard spreadsheet program, save as CSV, then import. The tool will then automatically create and assign BACnet objects. You can also start with a BACnet object list, saved as a CSV file, and import the object list. The tool will automatically assign Modbus registers. Or you can specify the complete mapping of BACnet objects to Modbus registers in a CSV file and import that.

You do not need to start with a CSV list. The user friendly tool provides templates to build a complete configuration from scratch. The configuration tool also provides the means to allocate the gateway's object pool to Analog, Binary, or Multi-state type objects, as Inputs, commandable Outputs, or Value objects.

Models BB2-3060 and BB3-7301 can both be used as an MS/TP to Modbus TCP gateway. Which one should you use?

If you are familiar with the BB2-3010 Modbus RTU to BACnet MS/TP gateway, and would like to use a Modbus TCP version of the same gateway using the same configuration tool, then the BB2-3060 is the better choice. Some will find the Windows based configuration tool for the BB2-3060 to be more convenient than the web based configuration of the BB3-7301.

If you are already familiar with other Babel Buster models having a web user interface, then the BB3-7301 will have a familiar look and feel. However, because the BB3-7301 is also a BACnet router, it will potentially cause problems if you do not disable routing when there are other routers on the network and you only want to use the BB3-7301 as a gateway. If you prefer web based configuration, then the BB3-7301 is a good choice for you.

If you have no prior experience with any models, then we recommend the BB3-7301 as it requires no additional configuration software and does not require the MTX002 USB to MS/TP interface to connect for purposes of configuring the gateway. In addition, the BB3-7301 gives you higher performance and higher capacity (can map more points) at a lower cost.

Find out more about the BB3-7301 here.


BB2-3060 Features

• Read/Write Modbus registers via BACnet objects
     • 300 Non-commandable objects OR
     • 135 Commandable objects OR
     • Between 135 and 300 objects of mixed types.
     • Object allocations are user configurable
• AI, AO, AV, BI, BO, BV, MSI, MSO, MSV objects
• COV, COVP subscription support
• BACnet slave is Modbus TCP master or vice versa
• Bidirectional communication between BACnet and Modbus
• Supports Modbus “coils”, input registers, holding registers
• Single or double Modbus registers
• Signed, unsigned, IEEE 754, single bit
• Modbus register mapping configured via object properties
• Modbus registers may be scaled
• Modbus (master) polling interval configurable per point
• Commandable BACnet objects implement priority array
• Hardened EIA-485 transceiver for MS/TP ports
• MS/TP baud rates: 9600, 19200, 38400, 76800
• 10/100BaseT Ethernet, RJ45 connector, for Modbus TCP
• Powered by 10-30VDC or 12-24VAC 50/60 Hz
• Power Consumption: 0.3A @ 24VDC
• DIN rail mounting, 100mm H x 70mm W x 60mm D
• Pluggable screw terminal blocks
• Operating temperature -40°C to +85°C
• Humidity 5% to 90% non-condensing
• Listed to UL 916 and (Canadian) C22.2 No. 205-M1983
• FCC, CE Mark


• BB2-3060 Data Sheet

• BB2-3060 User Guide

• BB2-3060 Support Package
Contains configuration tool software, USB driver, documentation.

• Modbus Tutorial
Introduction to Modbus, including function codes, exception codes, register numbering.

• BACnet Tutorial
Introduction to BACnet

BB2-3060 Video Library

Watch these videos for an introduction to configuring the gateway. It's easier than reading!

Introduction to BB2-3060 Gateway Configuration Tool

Mapping Modbus Registers with the Configuration Tool

Mapping BACnet Objects with the Configuration Tool

BACnet Object Allocation in the Configuration Tool

CSV to XML Conversion Tool

Babel Buster Configuration Builder

The Configuration Builder software available for use with the web based gateways (such as BB2-7010) is not needed for the BB2-3010 or BB2-3060 because CSV import capability is already included in the configuration tool for the BB2-30x0 gateways.

The CSV import simplifies the process of creating or changing a large number of entries because you can use any standard spread sheet program to manipulate the content of one or more CSV files, and then import that configuration to be loaded into the gateway. If the gateway will be reading a long list of Modbus registers, for example, you can sometimes just copy a list of registers from another source, paste into a simple text file, and import that into the spread sheet program. Then add a header line to label the content, add a handful of additional columns, and you quickly have most of a complete configuration. Very often, the only thing that changes from one line to the next is the register number. The other entries can be quickly made by entering once and using the spread sheet program's "fill down".

Get the Tool Now!

This tool is free and available for download now. Unzip and run the BB2-MSTP-Modbus_Setup.exe file. Open the program, and click the help icon (blue question mark in upper left corner) to access the user guide.

Download the Babel Buster Configuration Tool here.

CSV to XML Conversion Tool

Configuration Service

Need even more help with your network gateway configuration task? We can do the configuration for you, or at least give you a big head start. We are working on building a library of configuration files for commonly used devices. If yours isn't already in the library, we will add it. To get started, open a support ticket and attach a copy (typically a .pdf document) of whatever documentation you have for your device. In addition, provide a list of the registers or objects you want to read or write. Of course, you can also start by asking if we already have that device in our library. If you have a proprietary application that you do not want included in our library, you can hire us at a very reasonable rate to do custom, proprietary configuration work for you, too.

Our most extensive technical support is provided by the same engineering staff that developed the products. Your personal attention from this staff is available via the support ticket system.

No user/password is required to open a new ticket. Once you open a ticket, you will immediately receive an email with your ticket number. Your ticket number becomes your login to review your ticket(s) later. Click the Support Ticket icon anywhere you see it. (If you do not get an email with your ticket number, within minutes, check your junk folder, spam settings, etc, and try again if necessary.)

 Open a Ticket