The Babel Buster SPX-B Modbus to BACnet IP gateway allows Modbus devices to communicate with BACnet IP devices. BACnet objects may be read as Modbus registers, and Modbus registers may be read as BACnet objects. The Modbus to BACnet IP gateway acts as a translator between the two protocols.

The Modbus to BACnet IP gateway may be both Modbus TCP client and server at the same time, and can be configured to also be a Modbus RTU master or slave that runs independently of Modbus TCP. The SPX-B will continuously poll Modbus registers in TCP or RTU devices and make that data accessible as BACnet objects. Configured to go the other way, the SPX-B will continuously poll objects in other BACnet devices and make that data accessible as Modbus registers for other Modbus masters polling the SPX-B.

BB2-7010 Modbus to BACnet IP Gateway Functionality

An available variation of the SPX-B also includes an SNMP client and server that translates and shares data between BACnet IP and SNMP devices. The SNMP agent (server) also has the ability to send traps on threshold rules set by the user.

Feature Highlights
• Connect BACnet IP Devices to a Modbus RTU or TCP Network
• Subscribe to COV on Changes from Modbus or BACnet
• Up to 1000 BACnet Objects and 1000 Modbus Holding Registers
• BACnet Input, Value, Output objects for Analog, Binary, Multistate
• Optional mapping of Modbus Registers as Coil, Discrete, Input, Holding
• Optional SNMP client and server, includes trap send on threshold
• FCC, CE Mark
• Software Included, No Drivers to Buy

Babel Buster BB2-7010 BACnet IP to Modbus or SNMP Gateway

Babel Buster SPX-B Modbus to BACnet IP Gateway

Order code: SPX-B
List price: $524.00
Retail price: $419.00

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SPX-B Base Model with Modbus Support

Babel Buster SPX-B BACnet IP to Modbus Gateway provides a BACnet IP client and server, Modbus TCP client and server, and Modbus RTU port configurable to be master or slave. Most often used to connect Modbus devices to a BACnet IP network, the SPX-B is configured via simple web page templates to read and write Modbus registers in one or more Modbus slaves, making that data accessible as BACnet objects on the BACnet IP network.

The SPX-B includes a BACnet IP client which allows BACnet IP devices to be accessible from Modbus TCP or RTU. You configure the device instance, object type and instance, and poll interval for reading or writing BACnet objects. The object data is stored in the SPX-B server for subsequent retrieval by any supported remote client (or master). The same polling schemes that apply to Modbus also apply to remote BACnet IP slaves polled by the SPX-B's BACnet IP client.

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.

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 well with the Modbus Holding register.

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.

SPX-B with SNMP Support

The standard model SPX-B1 provides Modbus and BACnet IP clients and servers. The SPX-B2 adds an SNMP client and server. The combination of SNMP agent (server) and BACnet IP client makes BACnet IP devices accessible from SNMP. The SNMP client allows SNMP devices to be accessible from BACnet IP or Modbus. You configure the remote SNMP agent's IP address, the OID of the MIB variable you wish to poll, and set a polling interval. The object data is stored in the SPX-B server for subsequent retrieval by any supported remote client.

The SPX-B includes its own internal web server that provides a web based user interface for configuring the SPX-B. Configuration is done using simple templates, and each web page has an online help section at the bottom.

Screen shot from BB2-7010 BACnet IP to Modbus Gateway

Click on any of the links below to view a demo copy of the entire Web UI in the SPX-B. Note: These demo web copies are taken from a BB2-7010. The SPX-B web UI is identical.

 BB2-7010-01 Demo Web - Identical to SPX-B1

 BB2-7010-02 Demo Web - Identical to SPX-B2


SPX-B Features

• Read/Write any standard Modbus register via BACnet
• Read/Write any standard BACnet object via Modbus
• Bidirectional communication between BACnet and Modbus
• Supports Modbus coils, input registers, holding registers
• Single or double Modbus registers
• Signed, unsigned, IEEE 754 Modbus registers
• Supports Mod-10 format (2, 3, 4-register)
• Modbus register mapping configured via web interface
• Modbus registers may be scaled (x10, x0.1, etc.)
• Modbus (master) polling interval configurable per point
• Commandable BACnet objects implement priority array
• Hardened EIA-485 transceiver for Modbus RTU
• 10/100BaseT Ethernet for BACnet IP and Modbus TCP
• Powered by 12-24V DC/AC 50/60 Hz
• Power Consumption: 0.1A @ 24VDC
• Panel mount, 70mm H x 131mm W x 38mm D
• Pluggable screw terminal block for power & RTU network
• Operating temperature -40°C to +85°C
• Humidity 5% to 90% non-condensing
• FCC Class A, CE Mark

Maximum Object Counts and System Capacities for SPX-B

SPX-B1: Pool of 1000 objects
SPX-B2: Pool of 500 objects

The object pool may be allocated among the following object types, with a minimum of 1 per object type: Analog Input, Analog Output, Analog Value, Binary Input, Binary Output, Binary Value, Multi-state Input, Multi-state Output, Multi-state Value.

• Maximum 250 Binary objects with state text
• Maximum 1024 states for Multi-state objects with state text, actual number of objects/states supported varies by resource usage per object.

Useful object counts may be further limited by configuration file size which varies with use of character strings for object names, descriptions, and state text. MIB walk is limited to approximately 300 to 400 objects.

Additional maximum counts:
• Maximum BACnet IP device count 50
• BACnet IP Client read rule count 1000
• BACnet IP Client write rule count 1000
• COV Subscription capacity 1000
• Maximum Modbus RTU device count 240
• Modbus RTU read rule count 1000
• Modbus RTU write rule count 1000
• Maximum Modbus TCP device count 50
• Modbus TCP Client read rule count 1000
• Modbus TCP Client write rule count 1000

SPX-B Video Library

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

The following video collection was recorded using the BB2-7010 gateway. The SPX-B is functionally identical to the BB2-7010, and therefore these discussions of the BB2-7010 also apply to SPX-B.

Introduction to the SPX-B and BB2-7010 BACnet-Modbus Gateway

Getting Started with the SPX-B or BB2-7010

Minimum Configuration - Ports and Object Allocation

BACnet Server - Object Overview

Configuring Modbus RTU Master

Configuring Modbus TCP Client (Master)

Configuring BACnet Client

Configuring Modbus RTU Slave

Configuring Modbus TCP Server (Slave)

HTTP Client - Overview of HTTP Data Push

Configuring SNMP Server (Agent)

Configuring SNMP Client (Manager)

Configuring BACnet BBMD

CSV to XML Conversion Tool

Babel Buster Configuration Builder

You would normally use the web pages found in the gateway itself to configure the gateway. But you may be able to take a shortcut if you have a long list of registers already in CSV file format.

The Babel Buster Configuration Builder is used to facilitate building of configuration files (aka "profiles") for Babel Buster network gateways by converting XML files to CSV files and vice versa. This 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 convert that into an XML configuration file that can 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".

The Babel Buster Configuration Builder simplifies the process of making global changes to a large number of gateway register or object "maps". The gateway “converts” protocols by querying devices on one network with one protocol, and then saving that data internally so that it may be accessed on another network using a different protocol. The designation of what should be queried is referred to as a “map” in the gateway. In most applications, most or all maps are “read” maps, meaning the gateway will read data from some other device. A “write” map will write data to that device. Most often the gateway will actively read data from a device and passively wait for another device on the alternate network to query the gateway to obtain that data. But it is also possible to configure the gateway with two sets of maps, one to actively read device A using protocol A, and then actively write that data to device B using protocol B. The process can also be reversed, and can be done concurrently. You may both read and write data on one network while writing and reading data on the other network.

What to Expect from the Conversion Tool

The point of this configuration builder is to simplify the process of entering long lists of registers or objects. Where most of the parameters are the same for many maps, using a spread sheet program's "fill down" makes the process fast and easy.

There are situations where creating a CSV file for configuring some aspect of the gateway is actually going to create more work than simply using the web UI or PC based software to directly configure that aspect. Configuring the Modbus RTU port baud rate is one such example. There is only one setting. A CSV file would create more work rather than less, as intended. Therefore, the configuration builder only supports CSV import/export for those aspects of gateway configuration that involve long lists of largely replicated parameters. There are a very limited number of list type entries that are not supported in part because they are seldom used, and in part because very little of the list is replicated from one entry to the next. The BACnet Broadcast Distribution Table is one such example.

Do note, however, that if you have already done a lot of configuration, have saved that to an XML file, and want to add a list from a CSV file, you can do that. Refer to the section in the user guide that talks about modifying an existing configuration.

Get the Tool Now!

This tool is free and available for download now. Unzip and run the bb-builder-setup.exe file. Open the program, and click the help icon (blue question mark in upper left corner) to access the user guide. The very first section tells you how to get started.

Download the Babel Buster Configuration Builder 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