Modbus RTU Server Serial

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Product Overview

The Modbus RTU Server Serial device driver works in conjunction with KEPServerEX to provide data exchange between OPC clients, Modbus Masters, and Modbus RTU networks. The Modbus RTU Server Serial driver allows a OPC client application to appear as 1 to 247 Modbus RTU devices on the network. The slave mode allows the server to receive data by exception from a Modbus RTU master. Typical applications include connectivity with larger DCS systems that utilize Modbus RTU. As with any slave device, the Modbus RTU Slave driver will only transfer data when being read or written by a RTU master. Data integrity is ensured with our extensive error handling.



  • Word Order Swapping for Floating Point and Longs
  • Modbus RTU Multi-drop Supported
  • Full Address Range Support (0 - 65535)
  • Hex Addressing Support (0-FFFF)
  • Can appear as Multiple Modbus Slave devices
  • Data Modbus RTU functions accepted by Slave: 01, 02, 03, 04, 05,
  • Adjustable Address Base (0 or 1)
  • Station numbers selectable from 1-247


  • Modbus RTU Protocol

Supported Devices

  • Any Modbus compatible devices

Available Languages

  • English
  • German
  • Japanese
  • Simplified Chinese

Application Support

  • DDE Format CF_Text and AdvancedDDE
  • NIO Interface for iFIX
  • OPC .NET Service (OPC .NET) Version 1.00
  • OPC Alarms and Events (OPC AE) Version 1.10
  • OPC Data Access (OPC DA) Versions 1.0a, 2.0, 2.05a, and 3.0
  • OPC Unified Architecture (OPC UA) Clients
  • SuiteLink and FastDDE for Wonderware

Release Notes



  • Removed non-inclusive terms out of respect for users of our software. Renamed this driver in compliance with updated terminology.  



  • The driver no longer sends a response to an invalid transaction.



  • Added Chinese language support.



  • Added German language support.
  • Added Japanese language support.



  • Fixed an issue where a buffer overflow could result in the driver writing to erroneous coils.



Increased the character limit of the tag Description field from 64 to 255.


  • The driver will now check for License Activation upon receiving unsolicited communications.


  • Added string data type support for Internal Registers.

What Is a Driver?

KEPServerEX is more than an OPC server—it's a connectivity platform for industrial automation and IoT. Simply download KEPServerEX, and then select from Kepware's library of more than 150 device drivers, client drivers, and advanced plug-ins to fit the communication requirements unique to your industrial control system.

A driver is a software component that enables KEPServerEX to meet the connectivity requirements of a specific device, system, or other data source. The driver handles all proprietary communications to the data source for KEPServerEX; the client interfaces handle all supported OPC, proprietary, and open standards connectivity to applications that monitor or control the devices.

Drivers may be licensed individually or in suites. Additional drivers can be licensed on demand as connectivity needs evolve.