Instrumentation

1. Introduction In industrial automation systems, especially in power plants and petrochemical industries, the 4–20 mA current loop remains the most widely adopted standard for analog signal transmission. Compared with voltage signals (e.g., 0–10 V), the 4–20 mA signal offers superior noise immunity, long-distance transmission capability, and inherent safety, making it the preferred choice in […]

Company: Dalian Zero Instrument Technology Co., Ltd.Document Type: Standard Operating Procedure (SOP)Effective Date: 18th Sep 2025Version: V1.0 1. Scope This document specifies the inspection, zero-point calibration, and maintenance procedures for common industrial instruments, including flowmeters, level transmitters, pressure transmitters, and valves. It is applicable to on-site commissioning, preventive maintenance, troubleshooting, and periodic inspection in chemical, petrochemical,

In a chemical plant, instruments are essential for monitoring operational status. Their parameters are crucial for safe production and producing compliant products. Therefore, chemical instrument inspections are not merely routine tasks but essential checks for identifying hazards, reducing risks, and ensuring product quality. Without adequate inspections, complex chemical processes and high-speed equipment operations can result

Introduction Hydrogen (H₂) and nitrogen (N₂) are two of the most important industrial gases, widely used in industries ranging from chemical synthesis and metallurgy to energy and electronics. Monitoring their purity and mixture ratios is crucial for process efficiency, safety, and product quality. In practice, users often face a choice: should they use a single

1. Introduction In process control, the Proportional–Integral–Derivative (PID) controller is one of the most widely used strategies.However, when the setpoint (SP) undergoes a sudden step change, the standard PID often causes controller output overshoot, valve oscillations, and mechanical stress.To address this issue, an improved structure known as Proportional–Derivative First (PD–PI) Control has been developed. This

1. Introduction In modern manufacturing enterprises, the integration of Distributed Control Systems (DCS) and Enterprise Resource Planning (ERP) systems is a cornerstone for digitalization and smart manufacturing. While DCS focuses on real-time process monitoring and control at the plant floor, ERP emphasizes resource planning, scheduling, and cost management at the enterprise level.Bridging these two systems

1. Introduction Flame detectors are critical components of boiler furnace safety supervision systems (FSSS). Their primary function is to monitor combustion status in real time and provide signals once flame instability or extinction occurs, ensuring the timely shutdown of fuel supply. Among flame detectors, infrared (IR) flame detectors and ultraviolet (UV) flame detectors are the

Selecting the right instrumentation is a critical aspect of ensuring the safety, stability, and efficiency of chemical processes. The selection process must take into account a variety of factors, such as process conditions, medium characteristics, environmental requirements, and measurement precision. This guide outlines the key steps and considerations to help streamline the selection process. 1.

In large-scale chemical control systems, a typical structure involves a hierarchical separation of control and optimization layers based on time scales. The system is divided as follows: Basic Control (seconds) Advanced Control (minutes) Real-time Optimization (hours) Scheduling (days/weeks) Planning (months/years) This separation simplifies complex problems by addressing different time scales in distinct layers. Can Advanced

Abstract In hazardous-area automation projects, the choice of explosion-proof type is a fundamental engineering decision. While two-wire transmitters are commonly designed as intrinsically safe (Ex i), engineers often ask whether four-wire instruments can also achieve intrinsic safety. This paper provides a comprehensive analysis from the perspectives of power consumption, energy limitations, international standards, and engineering