Understanding PLC Communication: Application and Programming of MODBUS Protocol

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

God Mode of IoT Devices: Insights from 2017 Security Developer Summit

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

Thoughts on Serial Communication Design with 51 Microcontroller

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

Mastering RS485: Data Transmission Basics

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

RS-232-C Serial Port and Cable Usage Instructions

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

Solving USB to TTL Board Programming and Serial Debugging Issues for STC

Problem: I used a USB to TTL board to program the STC89C52RC microcontroller. I connected the board’s RX to the microcontroller’s TX (P3.1), the board’s TX to the microcontroller’s RX (P3.0), and GND to GND. After making the connections, I couldn’t download the program, and I kept receiving the prompt “Please power on the MCU.” … Read more

Industrial Control Basics: Serial Data Capture and Simulation

Introduction In industrial control sites, there exists a fundamental yet easily overlooked aspect that all devices rely on—serial ports. So, what is a serial port? Is there a risk associated with serial communication? Qi’an Technology’s classroom provides answers and details how to conduct safe offense and defense regarding serial ports. What is a Serial Port … Read more

How to Gain Local Shell Access on IoT Devices

This article is a featured post from the KSY Forum by author ID: fengzhidian 1. Introduction The author has recently researched several smart home devices, which have fewer open ports and are generally unable to obtain debugging permissions from the network side. Gaining local debugging permissions on the device has become an important step in … Read more

How to Effectively Use ESP8266 and STM32

Although the ESP8266 programs and related products have matured significantly, some beginners still don’t know how to learn. For example, how to use an ESP8266 along with an STM32 microcontroller to create a small product? What is the learning path like? How should we get started? In this regard, I suggest: 1. First, study the … Read more

Modbus-RUT Tutorial for Huichuan AM401 PLC

Search on WeChat Technical Training Preparation: Hardware: Huichuan AM401 PLC, one USB to RS485 converter. Software: InoProShop (V1.6.2), Serial Assistant, Modbus-RUT slave simulator. Serial Debugging Process: 1. Program the PLC. 2. Use the Serial Assistant to check if the characters sent by the PLC are correct. 3. Connect the actual device for PLC-device debugging. (You … Read more