Key Points of Modbus-RTU Communication with S7-1200 CM1241

Recently, I used the S7-1200 to collect data from a certain flow sensor via Modbus-RTU. The Siemens side chose the CM1241 (RS422/485) (order number 6ES7 241-1CH32-0XB0, firmware version V2.2), and the CPU is 1214C with firmware version V4.2. I thought the debugging would be simple, but it took a lot of time, and I consulted … Read more

Modbus-RTU Communication Example with Siemens PLC

WeChat Search Technical Training 01 Hardware Setup The Modbus communication in the program is conducted between the 0 communication ports of two S7-200 CPUs (it is best if each CPU has two communication ports). On the master side, communication can also be established using the corresponding library files “MBUS_CTRL_P1” and “MBUS_MSG_P1” through communication port 1. … Read more

Controlling Inverters with Siemens PLC via MODBUS

9 Online Siemens TIA Portal PLC Training Camp Registration Open on August 7 Siemens PLC Practical Training Class in Qingdao on August 18 1. Overview of MODBUS Communication The MODBUS protocol is divided into two types: MODBUS protocol over serial links and MODBUS protocol based on TCP/IP. The serial link MODBUS protocol includes MODBUS ASCII … Read more

Beginner’s Guide to TIA Portal: MODBUS-RTU Communication Configuration

Hello everyone, good evening! Beginner’s Guide to TIA Portal: MODBUS-RTU Communication Configuration Continuing from the previous article, we will explain how to use MODBUS communication commands. MODBUS communication requires three commands: ① MB_COMM_LOAD command ② MB_MASTER command (Master command) ③ MB_SLAVE command (Slave command) The communication commands are located in Communication – Communication Processor – … Read more

Steps and Key Points for Modbus TCP Communication with Siemens PLC S7-200SMART

Search on WeChat Technical Training Modbus TCP is a very traditional and widely used communication protocol, and many smart devices support this protocol. Siemens S7-200SMART and the 1200 and 1500 series support it for free (300 and 400 series incur high fees), and it has been made into a standard library, making it very convenient … Read more

Understanding RS232, RS485, RJ45, and Modbus Protocols

Consider a DC power supply with an output socket interface that has three pins: positive, negative, and ground. Accordingly, the load’s plug should also have three pins corresponding to the power side to correctly obtain power supply. Note that there are three essential conditions that must be met: The first is that the shape, size, … Read more

Mitsubishi FX2N PLC and Mitsubishi Inverter Modbus RTU Protocol Communication Application

Search on WeChat Technical Training Modbus is a serial communication protocol invented by Modicon for communication between PLCs and hosts. Its physical layer uses asynchronous serial standards such as RS232 and RS485. Due to its openness, it has been adopted by numerous PLC and RTU manufacturers. The Modbus communication method adopts a master-slave query-response mechanism, … Read more

Overview of Modbus Communication – Series 17

Click Jicheng Training WeChat Follow me! ☀ Jicheng Training Network’s official WeChat is the most professional and concentrated in the industrial control field, providing technical sharing, free videos, and a communication platform. Follow Jicheng, and there will be no problem in improving your skills! 1. Overview All the content that needs to be discussed regarding … Read more

Understanding RS232, RS485, RJ45, and Modbus Protocols

Imagine a DC power supply with an output socket interface that has three pins: positive, negative, and ground. Correspondingly, the load’s plug should also have three pins that correspond one-to-one with the power supply side to correctly obtain power supply. Note that there are three essential conditions that must be met: The first is that … Read more

Introduction to Industrial Control Security: Modbus

The field of industrial control security is relatively closed, with few public resources available. I read “Hacking Exposed Industrial Control Systems,” a book from 2016, and selected some chapters for translation as a starting point. MODBUS Modbus is a serial communication protocol created in the late 1970s by Modicon (now Schneider Electric) for use with … Read more