libmodbus

Implementing Modbus Protocol for Communication Between Microcontrollers and PLCs

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Implementing Modbus Protocol for Communication Between Microcontrollers and PLCs

1. Introduction The HMI (Human-Machine Interface) is increasingly used in industrial automation systems and devices due to its small size, high performance, and strong real-time capabilities. It features various displays such as letters, Chinese characters, graphics, and images, with a simple and user-friendly interface. Equipped with long-lasting membrane button keyboards, it is easy to operate. … Read more

Common Communication Protocols for PLCs

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Common Communication Protocols for PLCs

Before we start this topic, we should understand a commonly confused issue. The difference between RS485 and MODBUS: RS485 is a physical interface, simply put, it is hardware. MODBUS is an internationally standardized communication protocol used for data exchange between devices from different manufacturers (generally for industrial purposes); the so-called protocol can also be understood … Read more

Understanding RS232, RS485, RJ45, and Modbus Protocols

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Understanding RS232, RS485, RJ45, and Modbus Protocols

Imagine a DC power supply with an output socket that has three pins: positive, negative, and ground. Correspondingly, the load’s plug should also have three pins that match the power supply side, allowing for correct energy supply. Note that there are three essential conditions to meet: The first is that the shape, size, and pin … Read more

Step-by-Step Guide to Modbus Communication

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Step-by-Step Guide to Modbus Communication

Search on WeChat Technical Training This article will introduce the detailed steps for Modbus communication between the S7-1200 PLC and the V20 frequency converter. 1. Find an S7-1200 PLC with an RS485 communication module and a V20 frequency converter. 2. Connect the RS485 module to the V20 frequency converter. The wiring method is to connect … Read more

Example: Controlling Inverters with Siemens PLC via MODBUS

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Example: Controlling Inverters with Siemens PLC via MODBUS

1. Overview of MODBUS Communication The MODBUS protocol consists of MODBUS protocol over serial links and MODBUS protocol based on TCP/IP. The serial link MODBUS protocol includes MODBUS ASCII (string) and MODBUS RTU. The MODBUS protocol library provided by 200SMART supports MODBUS RTU communication. MODBUS RTU sends data in hexadecimal values. MODBUS ASCII sends data … Read more

Modbus Simulation – Essential Skills for Beginners

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Modbus Simulation - Essential Skills for Beginners

Modbus Simulation – Essential Skills for Beginners In the field of industrial automation, we often encounter various communication protocols, such as Profibus, ControlNet, Ethernet, Canopen, and Modbus. Among these, the Modbus protocol is the most widely used, free, and open-source, and is supported by almost all manufacturers’ industrial equipment. When working on engineering projects, we … Read more

Modbus Protocol and Implementation Tutorial

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Modbus Protocol and Implementation Tutorial

Modbus Introduction A brand new, customizable Modbus. This is a version you have never seen before. Easy to port and easy to use, with plenty of comments that you will love. The Modbus protocol is the standard communication protocol for industrial control devices, details can be found in the encyclopedia description. Simply put, the Modbus … Read more

Debugging MODBUS Communication Issues

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Debugging MODBUS Communication Issues

Search on WeChat Technical Training In actual industrial automation applications, various communications are essential, such as PN communication, S7 communication, MODBUS TCP communication, and MODBUS communication, among others; however, the most widely used is MODBUS communication, as it is an open, free, and universal communication protocol. Often, during equipment debugging on the industrial site, communication … Read more

Detailed Explanation of ModbusTCP Protocol

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Detailed Explanation of ModbusTCP Protocol

Search WeChat Technical Training Introduction Modbus was developed by MODICON in 1979 and is a standard for industrial fieldbus protocols. In 1996, Schneider Electric launched the Modbus protocol based on Ethernet TCP/IP: ModbusTCP. The Modbus protocol is an application layer messaging protocol that includes three types of messages: ASCII, RTU, and TCP. The standard Modbus … Read more

Understanding the MODBUS Standard Protocol

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Understanding the MODBUS Standard Protocol

Search on WeChat Technical Training 1. What is MODBUS? 1. Basic Concepts MODBUS is a communication protocol initially advocated by MODICON (now a brand of Schneider Electric). It has gradually been recognized as a standard communication protocol through practical applications by most companies. As long as data communication or transmission follows this protocol, different systems … Read more