schneiderModbus Master (Serial and TCP/IP) Driver for Field Device System Integrator Modules

The Field Device System Integrator (FDSI) Modbus Master driver is designed to smoothly integrate single or 

dual-ported Modbus devices using several different Modbus protocols into an I/A Series® system.

FEATURES

Key features of the FDSI Modbus Master driver are:

 Integration of single and/or dual-ported Modbus 

devices into an I/A Series system at the fieldbus 

level

 Exchange of real-time data between Modbus 

devices and the I/A Series system

 Compliance with the globally accepted and 

widely used Modbus communication standard

 Simplex (FBM230 or 232) or Redundant 

(FBM231 or 233) operation of FDSI Fieldbus 

Modules

 Support for three Modbus protocols: Modbus 

RTU and Modbus ASCII protocols for serial 

devices, and Modbus/TCP for Ethernet devices

 Optionally available vendor-specific device 

variations of Modbus drivers 

 FDSI hardware provides a barrier for network 

security issues

 Availability of standard I/A Series plant 

management functions and operator displays to 

Modbus devices

 System Monitor detection of Modbus device 

connectivity

OVERVIEW

The Field Device System Integrator (FDSI) Modbus 

Master driver enables the integration of vendorindependent single or dual-ported Modbus devices 

using one of several Modbus protocols into an 

I/A Series system.

The Modbus Master driver allows the I/A Series 

system to obtain real-time data from attached 

Modbus devices, manipulate the data using state-ofthe-art control algorithms, and write output data to 

the devices. 

The Modbus Master driver is downloaded to the 

appropriate single or redundant FBM, and allows the 

FBM to translate the data sent to the I/A Series 

system from the field device or vice-versa. 

Figure 1 illustrates a typical configuration in which a 

simplex FBM230 is communicating with serial 

Modbus devices. Figure 2 illustrates a typical 

configuration in which an FBM is communicating with 

Ethernet Modbus devices.

HARDWARE

Devices with which the FDSI FBMs can successfully 

communicate are single or dual-ported Modbus 

devices that support any of the three Modbus 

communication protocols. Depending on which 

Modbus devices and methods of communication you 

are using, as well as redundancy requirements, you 

need one or more of the following FDSI FBMs.

FBM230

The FBM230 is equipped with four ports, each of 

which can be configured to use either the RS-232, 

RS-422, or RS-485 physical interface standard. The 

FBM230 supports single-ported devices utilizing 

either the Modbus RTU or Modbus ASCII 

communication protocols, and provides a serial 

interface between the I/A Series system and the 

devices. Refer to PSS 21H-2Z30 B4.

FBM231

The FBM231 is equipped with four ports, each of 

which can be configured to use either the RS-232, 

RS-422, or RS-485 physical interface standard. Two 

FBM231s can be used to implement a redundant 

serial interface between the I/A Series system and 

dual-ported devices utilizing either the Modbus RTU 

or Modbus ASCII communication protocols. Refer to 

PSS 21H-2Z31 B4.

FBM232

The FBM232 supports single-ported devices utilizing 

the Modbus/TCP communication protocol, and 

provides an Ethernet interface between the I/A Series 

system and the devices. Refer to PSS 21H-2Z32 B4.

FBM233

Two FBM233s can be used to implement a 

redundant Ethernet interface between the I/A Series 

system and single or dual-ported devices utilizing the 

Modbus/TCP communication protocol. Refer to 

PSS 21H-2Z33 B4.

MODBUS MASTER DRIVER BENEFITS

Using the Modbus Master driver with FDSI FBMs 

provides the benefits described in the following 

subsections.

Easy Integration of Modbus Devices

The Modbus Master driver allows you to include new 

or existing Modbus-compliant devices in your 

process, regardless of device manufacturer. 

Incorporating an open communication standard like 

Modbus in your system provides a wide range of 

options when selecting the best field devices for your 

process. 

I/A Series System Support

The I/A Series system supports three protocols for 

communication with Modbus devices: Modbus RTU, 

Modbus ASCII, and Modbus/TCP. For FBMs 230 and 

231, either Modbus RTU or Modbus ASCII are 

separately configurable on each port. This support 

accommodates the transfer of data to and from both 

single and dual-ported Modbus devices, via a serial 

or Ethernet connection. 

I/A Series software also provides standard plant 

management functions and operator displays for 

these devices, in addition to startup and 

communication fault detection and display using 

System Monitor.

Flexibility

The Modbus/TCP protocol uses Ethernet and TCP/IP 

technologies. The simplicity and low cost of Ethernet 

hardware combined with the high speeds and 

reliability characterized by Ethernet networks greatly 

improves plant efficiency and provides the flexibility 

required to constantly keep up with changing