PLC

In the evolving world of industrial automation, Model Predictive Control (MPC) is often positioned as the future of process control—boasting advanced features like constraint handling, multi-variable coordination, and performance optimization. But will MPC replace the time-tested PID (Proportional-Integral-Derivative) controller, which has dominated the industry for nearly a century? From a conservative engineering perspective, the answer […]

This article examines whether Safety Instrumented Systems (SIS) are required for Level-3 major hazard sources involving liquefied gases. The analysis is based on Chinese regulations, industry standards, and risk assessment methodologies. We explore key conditions under which SIS becomes necessary, especially for hazardous chemicals such as LNG, LPG, and liquid ammonia. 1. Regulatory and Standard-Based

1. General Principles for I/O Allocation 1.1 Redundancy Principle To comply with the single-fault tolerance requirement, redundant devices should be assigned to different controllers or I/O modules to ensure that failure in one does not affect the entire system. 1.2 Power Isolation Principle DO points may have different power sources (e.g., 24VDC or 220VAC, powered

1. Introduction In process industries, liquid level is a typical integrating process variable, representing the physical balance of inflows and outflows in a vessel. Due to its integrating nature, level control loops often exhibit a unique set of challenges when applying conventional PID tuning methods—especially regarding the integral time. One of the most common issues

In industrial automation, Programmable Logic Controllers (PLCs) are the backbone of reliable and repeatable control systems. But one common question from engineers and end users alike is: Can a PLC function without an HMI (Human-Machine Interface) or SCADA (Supervisory Control and Data Acquisition) system? The short answer is yes — a PLC can absolutely run

In industrial environments such as oil, gas, petrochemical, and chemical industries, safety is paramount. Many systems and concepts have been developed to mitigate risks and protect both personnel and infrastructure. Among these systems are SIS (Safety Instrumented System), SIF (Safety Instrumented Function), and SIL (Safety Integrity Level). Other related terms like SILa and SIL0 are

In chemical manufacturing, the stable operation of the DCS (Distributed Control System) is a cornerstone of both safety and efficiency. However, a seemingly insignificant issue such as an aging data cable can trigger serious chain reactions — including interlock activation, emergency shutdowns, and potential process disruptions. This case study details how a fault in a

In the realm of industrial automation, I/O (Input/Output) modules play a critical role in facilitating communication between the control system and the external devices that it manages. These devices could be sensors, motors, valves, or other hardware components. Without the I/O modules, automation systems would be unable to receive data from the real world or

In modern industrial automation systems, Distributed Control Systems (DCS) play a critical role in monitoring and controlling various process parameters. However, a common question arises during system configuration: Should every parameter in a DCS have an alarm? The short answer is: not necessarily. Over-alarming can lead to alarm fatigue, unnecessary operator stress, and ultimately reduce

In modern industrial systems, Distributed Control Systems (DCS) are widely used to monitor and control motor operation in real-time. One common issue that often arises during operation is a mismatch between the DCS feedback current and the actual motor current. This discrepancy, if not addressed properly, may result in control errors, false alarms, or even