Theoretically, the bandwidth of the RS485 bus is calculated based on the serial port rate, but in practice, there is a 20ms error.Theoretically:At 9600bps, transmitting 1 byte requires sending 10 bits (1 start bit, 8 data bits, 1 stop bit), so the time required to transmit 1 byte = 1 / 9600bps * 10bit = … Read more
This article will detail the Modbus communication configuration process between the S7-1200 PLC and the V20 inverter. 1. Required: One S7-1200 PLC with an RS485 communication module and one V20 inverter. 2. Wiring method for the RS485 module and the V20 inverter: Connect the red wire to the P+ terminal and the green wire to … Read more
After reviewing everyone’s private messages and comments, I found that there is a high demand for information on the Modbus master station, as well as interest in how to use DMA to improve communication efficiency. Lastly, there is also some interest in Modbus TCP. Over the past year, the timeline for introducing this series has … Read more
My Birth Serial communication is a commonly used communication protocol in industry, mainly RS232, RS485, and RS422. Any communication between two devices requires a communication protocol. Manufacturer A has developed a temperature sensor that uses the RS485 communication interface and defined Protocol A; Manufacturer B has also developed a temperature sensor, which similarly uses the … Read more
In the Inovance Inoproshop software, configure the RS485 master station for the AM500 series PLC (using Modbus RTU as an example). Inoproshop is developed based on Codesys, and its configuration method is more standardized and graphical. Below are the detailed steps: Part One: Hardware Connection (Same as AutoShop) Confirm the port: The RS485 port on … Read more
Hello everyone! Recently, a friend asked me why the Modbus communication between the PLC and the inverter was not working despite following numerous tutorials. I remember when I first started, I was just as confused, struggling with the wiring diagrams and making several mistakes in parameter settings before finally succeeding. Today, I will share the … Read more
Description: This article explains the application of MODBUS. Currently, the communication protocol between industrial control upper and lower machines predominantly uses MODBUS, highlighting the importance of machine-to-machine communication. 1. MODBUS System Framework Diagram 2. Application of MODBUS The underlying communication of MODBUS uses RS485 signals connected via twisted pairs, allowing for long transmission distances of … Read more
Title: The Concept of Bus Communication Control: Upgrading from RS485 to Two-Wire Bus First Paragraph: In modern industrial sites, the old model of the 485 bus often gives engineers headaches: polarity pairing, endpoint management, and long-distance transmission are easily interfered with, leading to high on-site maintenance costs and inflexible expansion. Faced with various industry scenarios … Read more
Serial Port refers to the serial interface, commonly known as the COM (Communication Port) interface. This is an “old” interface that was primarily introduced to connect computer peripherals, such as mice or modems. Since this interface typically appears in a 9 pin format, it is often referred to as the 9-pin serial port or DB9 … Read more
RS232 and RS485 are two popular serial data communication protocols established by the Electronic Industries Alliance (EIA) for communication between systems and peripheral devices. Although they have been largely replaced by the USB standard on the PC side, they are still widely used in the industrial control field. What is the RS232 Protocol? The RS-232 … Read more