Modbus TCP Server Source Code

Modbus TCP Server Source Code

The Fastest Way to Modbus TCP Enable Your Factory Floor Product

Datasheet Request Info

Modbus TCP is an Ethernet implementation of the widely supported, widely used Modbus RTU protocol. Modbus RTU is the easy-to-implement Master/Slave communications protocol built by Modicon in the late 1970s. Modbus RTU achieved incredible penetration into many markets and applications because of its sheer simplicity. With a very small command set, easy to understand network representation and simple Request/Response message structure it became the defacto leader for communications between industrial devices. The biggest advantage for vendors implementing Modbus RTU is that it required no additional hardware other than a serial channel and a RS485 driver chip. Adding Modbus RTU could be accomplished with little expense, but end users suffered with very low throughput, troubleshooting and sometimes non-standard driver chip implementations.

Modbus TCP corrects those problems. Building on the simplicity of Modbus RTU and the desire for many customers to use Ethernet, Modbus TCP was created. Modbus TCP uses the identical command set, addressing modes and network representation as Modbus RTU. Effectively the same message that is transferred over RS485 using Modbus RTU is sent over a TCP/IP connection using Modbus TCP. Only the error checking bytes are eliminated as they are provided at the physical Ethernet layer. Using the identical message structure and network representation enabled many users to move their RTU applications to Ethernet.

You can now add Modbus TCP Server communications to your product quickly and easily with the Modbus TCP Server and Client development kit from Real Time Automation, Inc. Developed specifically for industrial platforms and fully integrated with any number of RTOS systems and TCP/IP stacks, you can have Modbus TCP Server communications in days not weeks, months or years. The development kit includes everything you need to implement your Modbus TCP networking solution; “no royalty,” single task source code, sample objects, PC Tools, a ready-to-run sample application, complete documentation and much more.

Real Time Automation supports many operating systems, but here are a few that are the most common:

  • Windows
  • VxWorks
  • Net Silicon
  • Rabbit
  • Quadros
  • Netburner
  • Freescale
  • Linux
  • Mentor Nucleus
  • Open TCP
  • Microchip
  • PowerQUICC II Pro


What to Do Next
Your next step is to contact the RTA Project Manager and schedule a telephone consultation to discuss your application.


  • Fully Compatible with any Berkley Sockets type TCP/IP Stacks
  • Easy-to-use Single Task Implementation
  • 100% “C” based source code
  • Fully Compatible with Modbus TCP Client Communications Module from many HMIs and PLCs
  • “No nonsense” Single Product Line licensing with no royalties
  • Easily Extensible, Table-driven object model structure
  • Ready-to-run, sample application that can be immediately compiled, downloaded and executed
  • Support Modbus TCP on most sockets-based TCP/IP stacks
  • Quickly and Easily Implemented
  • You Can Seamlessly Integrate Into Large Base of Rockwell Automation EtherNet/IP Systems
  • No Hassle From Burdensome Licensing Requirements
  • You Can Quickly Create Your Application From the Sample Object Definitions
  • No Risk Development – Guaranteed to Pass The Required ODVA Conformance Testing
  • You Can Get Started Immediately by Running The Sample Application