RS-232, RS-485, and RS-422 are common serial communication standards, each with unique characteristics and applicable scenarios. Below is a detailed analysis of these three communication standards: 1. RS-232 1. Origin and Purpose: ● Established by the Electronic Industries Alliance (EIA) in 1962. ● Aimed at solving low-speed, short-distance communication issues between early computers and peripheral … Read more
In scenarios such as industrial automation, building control, and energy monitoring, RS-485 serial communication is widely used for data transmission between devices due to itslong-distance transmission capability, strong anti-interference ability, and support for multi-node communication. Especially in a master-slave structure, RS-485 is an ideal choice for achieving centralized control and distributed sensing. However, during actual … Read more
RS-485 Communication Protocol Overview The typical serial communication standards are RS-232 and RS-485, which define voltage, impedance, etc., but do not specify software protocols. The RS-485 bus standard defines the electrical characteristics of the bus interface, specifically the definitions for two logic states: a positive level between +2V and +6V represents one logic state, while … Read more
The RS-485 bus is widely used in communication, industrial automation, and other fields. In practical applications, it is common to encounter questions about whether pull-up and pull-down resistors are needed and what resistance values are appropriate. Below, we will analyze these issues in detail. 1. Why are Pull-Up and Pull-Down Resistors Needed? 1) When the … Read more
Follow our official account to receive timely updates on new articles. Introduction: RS-232, RS-485 and RS-422 are standards defined and published by the Electronic Industries Alliance (EIA). EIA is an American industry association focused on developing and promoting standards in the electronics and electrical industries. Among these, RS-485 is highly praised and widely used in … Read more
1. RS-232 RS-232-C is a serial physical interface standard established by the Electronic Industry Association (EIA) in the United States. RS stands for “Recommended Standard,” 232 is the identification number, and C indicates the revision number. Its full name is “Serial binary data exchange interface technology standard between Data Terminal Equipment (DTE) and Data Communication … Read more
To build a stable and reliable Profibus-DP network, termination resistors can be considered a “small component with a big role”! Many engineers often overlook their importance, resulting in spending several days troubleshooting inexplicable communication failures, only to find out that it was the termination resistors causing the trouble. Today, we will analyze this seemingly simple … Read more
: Recently, I modified an old device that required communication control applications, from which I derived some insights: 1. FX2N-485-BD is economical to use; A./ (ASCII communication mode, operation, and frequency register address can be easily mistaken, but LRC checksum is easy to obtain)/ B../ (RTU communication mode, operation, and frequency register address is less … Read more
Abstract This article introduces the correct connection methods for RS-485 networks, including twisted pair wiring and recommendations for proper installation of termination resistors. It lists the receiver waveforms under correct and incorrect termination. This application note provides a basic guide for connecting RS-485 networks. The RS-485 specification (officially known as TIA/EIA-485-A) does not specifically dictate … Read more
The RS-485 bus is widely used in communication, industrial automation, and other fields. In practical applications, one often encounters the question of whether to add pull-up and pull-down resistors and what resistance values are appropriate. Below, we will analyze these issues in detail. 1. Why are Pull-Up and Pull-Down Resistors Needed? 1) When the differential … Read more