This article aims to give you a clear understanding of Modbus, summarizing related knowledge about Modbus, which is very suitable for beginners. If there are any errors, suggestions and modifications are welcome. What Is a Protocol? Before understanding what Modbus is, let’s first look at what a protocol is. A protocol is a Chinese term, … Read more
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
Today, let’s discuss Modbus. Here’s what we’ll cover: 1. Terminology Explanation 2. Background 3. Protocol Principles 4. Transmission Methods 5. Differences Between Modbus RTU and Modbus ASCII 6. Modbus TCP and Its Considerations 7. Function Code Roles 8. Security Analysis of Modbus Protocol 1. Terminology Explanation Checksum The checksum is usually the last digit of … Read more
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
1. Quick Ways to Learn Modbus 1.1 Register Mnemonics As a beginner, one might find the concepts of the Modbus protocol awkward, repetitive, and hard to distinguish, such as Coil Status, Discrete Input Status, Holding Register, and Input Register. Returning to the essence of the matter, in the field of industrial control PLC, it involves … Read more
Now, let’s explain the application of MODBUS. Currently, most industrial control communication between the upper computer and the lower computer uses the communication protocol MODBUS. It is easy to imagine the importance of communication between machines. 1. MODBUS System Framework Diagram 2. Application of MODBUS The underlying communication of MODBUS uses RS485 signals connected via … Read more
Editor’s Note: Currently, the security issues of IoT devices are mainly limited by hardware and software. Often, if the configuration does not keep up, even if developers want to address security issues, they may feel powerless. On the software level, the built-in protection mechanisms of the system are particularly critical, especially permission-based protections. We know … Read more
Recently, I needed to use the 51 microcontroller for some control tasks in a project. The main function is to receive commands from the host computer through the serial port, analyze and decode them, and wait for an external trigger signal to execute the previously received command actions. Fortunately, I had an STC89C52 on hand, … Read more
When it comes to communication, many people find it difficult and feel lost. I had the same feeling when I first encountered communication concepts. I gathered a lot of materials, mostly theoretical, and it always felt like I had no starting point. After finally understanding it, I realized that the main reason for not grasping … Read more
The serial interface, abbreviated as serial port, is also known as the serial communication interface (usually referring to the COM interface). It is an expanded interface that uses serial communication. If classified by interface, there are several types including RS-232, RS-422, and RS-485, among which the RS-232 serial port is the most commonly used serial … Read more