How to split Modbus protocol

Olga Weis
A common problem

In a network defined by the Modbus protocol, multiple devices can be used to transmit data to either a single controller or a server that has a Modbus driver installed. The Modbus server can handle input from multiple sensors through its communication port (eg. COM1). This port is controlled by a serial application which can make it difficult to open the port in multiple applications at the same time. But there is a software tool that makes it easy to allow more than one app to access the port simultaneously.

Modbus Splitter Software

Virtual COM Port Driver PRO by Eltima is the software application that enhances the capability of your Modbus network by allowing you to split Modbus data over virtual COM ports. It enables you to create virtual RS485 ports and split Modbus data so that all of the created ports simultaneously receive the identical data transmission. This allows you to take the data being received by the physical COM1 port and duplicate it to virtual ports such as COM2, COM3, etc. Multiple applications can access the real serial port by attaching to the virtual ports created by this Modbus data splitter.

Modbus data Splitter software

Virtual Serial Port Driver PRO is a versatile application that lets you split and join RS485 ports, create complex port bundles, and redirect the data from one port to another.
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Virtual Serial Port Driver PRO

Split COM port between several apps
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Virtual Serial Port Driver PRO

This Modbus data splitter software lets you create any number of virtual serial ports as you need. All of the virtual ports that you create will emulate the configuration and all parameters of the physical port that was used to create them.

Here are the steps to take in order to split one physical RS485 port into multiple virtual interfaces.

Step-by-step guide:

  1. Download Virtual Serial Port Driver PRO and install it on your computer.

  2. Launch the program and open the "Split" tab. Here you will select the physical port that you want to duplicate. Split Modbus data
  3. Click the "Add port" button to add the virtual ports which will be communicating with the physical interface that you are splitting. Create as many virtual ports as you need for your specific implementation.

  4. Select one of the newly created virtual ports to act as the main in the bundle and click "Set main".

  5. Click the "Add split port" button. The virtual serial port bundle that was just created will immediately appear in the Bundle tree. Split Modbus data over virtual serial interfaces

That’s all there is to it!

When your system’s physical serial port receives Modbus data the software will split Modbus protocol data so that it will also be sent to all connected virtual ports and applications.

Additional functionality of this communication software allows you to share a single physical serial port between multiple applications. You can set access rights ("Read", "Write", and "Control") individually for each application.

This versatile tool can make life much easier for those working with Modbus networks. Virtual Serial Port Driver PRO lets you split the Modbus protocol to allow multiple sources to access a single COM port. You can also redirect Modbus data between serial interfaces, join multiple physical ports into a virtual one, and create complex bundles of real and virtual ports.

Let’s explore this Modbus Splitter software’s key capabilities


Joining Modbus data streams

Virtual Serial Port Driver PRO lets you combine the data transmitted by any number of serial ports in a single virtual interface. A single application that is controlling the port can receive Modbus data from multiple devices or sensors.

Establishing a many-to-many port connection

A singular feature of Virtual Serial Port Driver PRO is its ability to create complex bundles. The bundle can be comprised of real and virtual ports in such a way that multiple interfaces on the "In" side can talk to multiple ports of the "Out" side. A "main port" for each side (IN/OUT) can be set to manage the serial ports control lines.

Creating port switcher

Some serial applications are limited in the number of ports they can work with simultaneously. VSPD PRO enables you to connect multiple physical ports into one virtual port to allow automatic switching to occur. VSPD PRO then interacts with a switcher created in your program that points to the virtual port. A free interface is detected from among the joined ports and supplied to the requesting application.

Virtual Serial Port Driver PRO is a great addition to the software toolbox of individuals working with serial communication protocols such as Modbus, RS-232, RS-485, and RS-422. The application provides essential features such as setting custom port parameters and creating port bundles.

VSPD PRO serves as an ideal solution for many communication tasks pertaining to serial ports. It builds on the distinctive features of Virtual Serial Port Driver and adds advanced functionality from a trio of Eltima’s Software products: Serial Splitter, Shared Serial Ports, and COM Port Redirector. The result is an all-purpose communication tool that allows you to extend the capabilities of your serial ports, applications, and devices.

Virtual Serial Port Driver PRO

Requirements: Windows (32-bit and 64-bit): 2008/ Vista/7/8/10, Windows Server 2012, Windows Server 2016 , 6.54MB size
Version 9.0.270 () Release notes