Instrumentation

1. Definition of Surge A surge (also called a transient overvoltage/overcurrent) refers to a short-duration pulse that appears on power or signal lines. Time scale: From nanoseconds to milliseconds. Amplitude: Peak values often exceed more than twice the steady-state voltage/current. Waveform: Typical waveforms include 1.2/50 μs voltage waves and 8/20 μs current waves. Essentially, a […]

Introduction High-risk process units in the chemical industry refer to facilities that involve highly reactive chemical processes (e.g., nitration, sulfonation, halogenation, strong oxidation, diazotization, and hydrogenation) or operate under extreme conditions such as high temperature (≥300 ℃), high pressure (≥10 MPa), and cryogenic environments (≤−29 ℃).In addition, high-risk storage units are facilities for storing toxic

Introduction Relays are essential components in modern industrial automation and power systems. They act as switching and protection devices, enabling safe and efficient control of electrical circuits. Depending on the application—whether for signal amplification, overload protection, safety shutdown, or high-frequency switching—different types of relays are used. This article provides a structured overview of the most

In industrial process automation, not every plant requires advanced control strategies. In many cases, well-tuned PID loops and simple control logic implemented in the DCS are sufficient to achieve stable and efficient operation. However, for more complex processes, relying only on PID optimization can be inadequate, and advanced process control (APC) becomes necessary. 1. Cases

In industrial instrumentation, theoretical knowledge is just like a wrench in your toolbox — it may not seem important at first glance, but when troubleshooting, it becomes indispensable. Whether preparing for certification exams or improving practical fieldwork, mastering instrumentation theory helps build a solid foundation. This document highlights several core concepts that often cause confusion

Introduction In industrial automation, RS-485 communication has become one of the most widely used methods for data exchange between devices. Thanks to its reliability, strong noise immunity, and long-distance capability, it is commonly found in factory automation, building control, and energy monitoring systems. However, RS-485 is not a single wiring method. It can be implemented

1. Introduction Steam temperature is one of the most critical parameters in thermal power plant operation. Compared with drum water level control, which has evolved into the classical three-element control system, steam temperature regulation remains highly complex. Multiple disturbance factors—ranging from load fluctuations to flue gas conditions and desuperheating water flow—can influence the dynamic behavior

1. Introduction The purpose of this document is to establish standardized requirements for the operation, inspection, maintenance, and overhaul of the Safety Instrumented System (SIS).The SIS is defined as an instrumentation system used to execute one or more Safety Instrumented Functions (SIF). It consists of sensors (e.g., switches, transmitters), logic solvers (controllers), and final control

This guide explains how to choose the installation height for combustible or toxic gas detectors based on whether the leaking gas is heavier or lighter than air. It also includes a special note for oxygen (O₂) sensors. 1) Classify the gas by buoyancy (relative to air) Let N = (gas molecular weight) / 29, where

To ensure the safety and reliability of instrumentation and control systems during seismic events, the following measures shall be adopted: 1. Anchoring of Instrument Equipment Instrumentation equipment such as control cabinets, auxiliary cabinets, instrument panels, instrument boxes, junction boxes, and field instruments shall be firmly fixed to floors or ground using foundations and supports.This prevents