PLC

In programmable logic controller (PLC) applications, discrete logic control refers to the processing of binary signals—on/off, true/false—based on specific logical relationships. This document outlines three commonly used programming approaches: Basic Logic Design, Advanced Logic Design, and Engineering Design Methods. 1. Basic Logic Design Method The basic logic design method uses simple logic operations (AND, OR, […]

In automatic control systems, achieving bumpless transfer is crucial. Bumpless transfer refers to the ability to switch between manual and automatic modes without introducing any disturbances into the process. Typically, switching from automatic to manual mode is straightforward. However, switching from manual to automatic mode is more complex and demands careful design. 1. Bumpless Transfer

1. Introduction In industrial process control, disturbances such as sudden changes in input or load conditions can significantly affect system stability. While PID controllers are widely used for maintaining process setpoints, combining them with feedforward control can enhance responsiveness and reduce output fluctuations. This paper discusses how feedforward and PID control can work together, using

Overview Safety Instrumented Systems (SIS) are the final line of defense in chemical and process industries. They protect personnel, equipment, and the environment from hazardous events by automatically transitioning processes into safe states under abnormal conditions such as overpressure, overtemperature, or high level alarms. However, interlocks can fail due to various reasons, often resulting in

This document outlines practical approaches for daily maintenance and troubleshooting of Distributed Control Systems (DCS), with a focus on power systems, network communications, and software-related issues. 1. Power Supply System DCS systems commonly adopt dual-redundant hot-swappable power supplies. Although DCS systems are generally stable during normal operations, faults—typically single-line power losses—can still occur. Prompt troubleshooting

Programmable Logic Controllers (PLCs) are widely used in industrial automation for their flexibility, reliability, and scalability. Based on their physical structure and configuration, PLCs can be generally classified into three types: Compact (Box-Type) Modular Embedded (Insert Board-Type) Each type has distinct design features, advantages, and typical applications, which are outlined below. 1. Compact (Box-Type) PLC

In high-risk industries such as chemical and petrochemical production, automation and instrumentation systems serve as the “central nervous system” of safe operations. Hidden failures or improper configurations in systems such as DCS, PLC, SIS, and GDS can lead to serious safety hazards. This document outlines key inspection guidelines and best practices based on GB, IEC,

Upgrading a Distributed Control System (DCS) is a significant undertaking for industries that rely on automated control systems. The decision involves weighing multiple technical, operational, and financial factors. This article explores when it is necessary to upgrade a DCS and provides detailed strategies to ensure a smooth transition to a new or improved system. I.

In the field of industrial communication, Modbus RTU and RS-485 are often mentioned together, leading many to mistakenly believe they are the same. In reality, these two concepts are fundamentally different—though they are tightly integrated in practical applications. What is RS-485? RS-485 is a physical layer communication standard, which defines how electrical signals are transmitted

In industries where durability, hygiene, and safety are paramount, equipment must be able to withstand not just regular wear and tear but also harsh cleaning procedures. This is where the IP69K protection rating becomes essential. This rating, one of the most stringent in the IP (Ingress Protection) system, ensures that devices remain functional even under