Instrumentation

In Distributed Control Systems (DCS), the integration of intermediate relays in Digital Input (DI) and Digital Output (DO) circuits, as well as safety barriers in Analog Input (AI) channels, is a common engineering practice. These components play critical roles in enhancing system stability, safety, signal integrity, and maintainability. This article explains the key reasons behind […]

In industrial automation and electrical control systems, especially within chemical plants, maintaining signal integrity and ensuring the safety of electrical components is critical. Three types of devices play essential roles in this protection framework: signal isolators, intrinsic safety barriers, and surge protection devices (SPDs). Each has distinct functions and principles, forming a multi-layered defense system

Introduction In modern industries such as manufacturing, scientific research, and healthcare, the accuracy of instruments directly impacts product quality, data reliability, and operational safety. To ensure precision in measurement, instrument calibration becomes a critical and often mandatory process. However, due to the complexity and resource demands of calibration, many organizations now choose to partner with

1. Background In a 1 million tons/year Fluid Catalytic Cracking (FCC) unit, the regenerated catalyst slide valve (commonly referred to as the “spent catalyst slide valve”) plays a critical role. It is used to: Cut off catalyst circulation during startup and shutdown; Regulate the catalyst circulation rate during normal operation to control stripper level and

In the field of industrial automation, interlock logic diagrams act as the “safety brain” of a system—precisely controlling equipment startup/shutdown, alarm responses, and emergency shutdown sequences. They are directly tied to personnel safety and the stable operation of multimillion-dollar facilities. An improperly designed reset switch can render interlock protection ineffective. Even worse, a small error

1. Introduction In process control systems, it is common to encounter situations where the effectiveness of one control loop depends on the status or mode of another. When this occurs, the loops are referred to as nested control loops. The most typical example is cascade control, but there are several other configurations, such as valve

In industrial environments, the integrity of instrumentation cable trays is essential for ensuring the safety and stability of control systems. A common but often overlooked safety hazard is the falling off of cable tray covers. This issue can lead to potential injury, equipment damage, or service disruptions. This article analyzes the main causes of cable

1. Overview of Push Buttons A push button is a type of manual control switch that is actuated by applying pressure using a part of the human body—typically the finger or palm. Equipped with a built-in spring mechanism for resetting, it is one of the most commonly used control devices in industrial and electrical systems.

Background In a 120,000 tons-per-year polyvinyl chloride (PVC) production facility, a critical incident occurred during the commissioning of newly installed valves on a liquid chlorine storage tank. The sudden shutdown was triggered by a tripped power supply circuit, which resulted in a full-scale plant stoppage and elevated the risk of hazardous chemical leakage. The root

Introduction In petrochemical production, automation instruments are the nervous system of the process. They play a critical role in ensuring operational stability, safety, and efficiency. Failures or inaccuracies in these instruments can lead to production losses or even severe safety hazards. This article presents a comprehensive methodology for troubleshooting typical issues in temperature, flow, pressure,