MODBUS RTU and TCP Client/Server Protocol for Simulink

Modbus Protocol

Test and validate Modbus communication directly from Simulink

Validate and test Modbus TCP and RTU devices such as programmable logic controllers (PLCs), protection relays, inverters, and sensors, directly from Simulink^®.

Leverage native Modbus TCP and RTU support via the Ethernet ports of your Speedgoat test system or use dedicated I/O modules to integrate Modbus communication directly into your real-time models. Automate testing workflows, validate system behavior under real-world conditions, and improve robustness by verifying behavior during timeouts, faults, and edge-case scenarios.

Request Workflow Demo

modbus

Key Capabilities

Speedgoat enables direct integration of Modbus communication into Simulink workflows, including:

Native Modbus TCP communication over Ethernet
Modbus RTU communication via serial interfaces
Client and server implementations within real-time applications
Simulink driver blocks representing full protocol functionality
Real-time execution and synchronized data exchange
Fault injection directly from Simulink via Modbus TCP to emulate faulty server behavior, and enabling realistic fault testing without external tools
Scalable simulation and testing by using a single Ethernet interface for multiple Modbus nodes

Selection Guide

Native Modbus TCP runs on the CPU. This is supported with onboard Ethernet interfaces and Ethernet I/O modules. One Ethernet port can handle the data transmission of multiple Modbus nodes configured in the real-time application (client, server, or both). Each Modbus node requires a run-time license. Native Modbus TCP support is available with MATLAB^® R2020b and later.

The following native implementations are available:

Product	Supported machines
Native Modbus TCP Client interface	Performance, Mobile, Baseline, and Unit real-time target machines
Native Modbus TCP Server interface	Performance, Mobile, Baseline, and Unit real-time target machines

In addition to onboard Ethernet support, native Modbus TCP is compatible with the following Ethernet I/O modules:

Product	Number of ports	Supported machines
IO710	1 port	Performance machine
IO715	4 ports	Performance, Mobile and Baseline real-time target machines
IO791	2 ports	Baseline and Unit real-time target machines

The IO75x I/O module series provides dedicated Modbus TCP I/O modules for single-node and multi-node applications. One module acts either as a single Modbus TCP node or a whole network of Modbus nodes. This solution ensures deterministic transmission of client queries and short response times to queries in the server because the protocol stack runs on the I/O module. IO75x I/O modules do not require run-time licenses.

Product	Description	Supported machines
IO753	Modbus TCP I/O module that acts as one client	Performance, Mobile, Baseline, and Unit real-time target machines
IO754	Modbus TCP I/O module that acts as one server	Performance, Mobile, Baseline, and Unit real-time target machines
IO754-32	Modbus TCP multi-node I/O module that simulates up to 32 servers	Mobile real-time target machine

Support for Modbus RTU is provided over serial I/O modules.

The following implementations are available:

Product	Supported machines
Modbus RTU Client interface	Performance, Mobile, Baseline, and Unit real-time target machines
Modbus RTU Server interface	Performance, Mobile, Baseline, and Unit real-time target machines

What is Modbus?

Modbus is a widely used communication protocol in industrial automation and power systems. It enables data exchange between devices such as programmable logic controllers (PLCs), sensors, actuators, and supervisory systems.

Two common variants are used:

Modbus TCP: Ethernet-based communication using standard IP networks
Modbus RTU: Serial communication over interfaces such as RS-232 or RS-485

Modbus follows a client-server architecture, where devices exchange data through structured requests and responses.

Modbus TCP Error Injection

Validate system behavior under faulty communication conditions and under normal operating conditions.

The Modbus TCP Error Injection block allows you to emulate faulty server behavior directly from Simulink Real-Time™, enabling realistic fault testing without external tools.

Simulate timeouts, invalid or inconsistent responses, and other communication issues to verify how your system handles edge cases and failures. This helps improve robustness, validate exception handling, and run repeatable negative tests as part of automated workflows.