Industrial automation systems are integrated systems that utilize control theory, instrumentation, computers, and other information technologies to detect, control, optimize, schedule, manage, and make decisions about industrial production processes, with the goal of increasing output, improving quality, reducing consumption, and ensuring safety.
System Composition
No matter how complex the structure, an automated system has the following main components:
Detector: Primarily used to obtain feedback information and calculate the difference between the target value and the actual value;
Controller: Equivalent to the brain's role in analysis and decision-making, determining in a timely manner what adjustments and controls the system should implement;
Actuator: Implements the decisions issued by the controller;
Object: The objective entity being controlled.
●Automation System Structure
Automatic control is a feedback-based technology. The elements of feedback theory include three parts: measurement, comparison, and execution. The variable of interest is measured and compared with the desired value; the deviation between the two is used to correct and regulate the system's response. Therefore, the core idea of automation technology is feedback, which establishes a connection between input (cause) and output (result). This allows the controller to determine the control strategy based on the actual input and output conditions to achieve the intended system function.
The system consists of two channels: a forward channel and a feedback channel. The forward channel is the main functional component for task execution.
Complex automated systems are often multi-variable, multi-loop, and multi-type systems.
●Main components and their functions
The controller – the brain of the system. In an automatic control system, the controller plays a crucial role, acting as the core of system management and organization. The performance of the system largely depends on the quality of the controller.
Actuators – In an automatic control system, actuators act like the limbs of a person. They receive control signals from the regulator, change the manipulated variables, and ensure the production process operates normally according to predetermined requirements. On the production floor, actuators directly control the process medium; improper selection or use can often lead to difficulties in the automatic control of the production process. Therefore, the selection, use, installation, and commissioning of actuators are crucial aspects.
Sensors – the eyes and ears of a system – are used to measure various physical quantities. Types include temperature sensors, flow sensors, pressure sensors, and so on. Sensors must meet reliability requirements. The raw information of the measured quantity is obtained from the sensor's output signal. If the sensor is unstable, its output signal will differ for the same input signal, resulting in an incorrect output signal and rendering the sensor ineffective.
●Traditional Control vs. Modern Control
PID control – proportional, integral, derivative
The PID controller, as the earliest practical controller, has a history of over 50 years and remains the most widely used industrial controller. PID controllers are simple to understand and do not require precise system models or other prerequisites for use, thus making them the most widely used controller.
Modern control includes optimal control, adaptive control, predictive control, and self-learning control.
Intelligent control – fuzzy control, expert systems, neural networks
● Sequential control and loop control
Sequential control switch logic control
Examples include relay matrix control and programmable logic controller (PLC) I/O module input/output control.
Loop control continuous regulation control
For example, the FM 458-1 DP application module is designed for free-configurable high-performance closed-loop control and technical applications such as motion control.
●Modern industrial automation systems
Modern industrial automation systems are an inevitable product of the large-scale, continuous, high-speed, and fast-paced production in modern industrial enterprises.
Basic Automation L1 (Control Layer): Field Equipment Control System
Process Automation L2 (Operational Layer): Production Process Monitoring System
Factory Automation Level 3 (Manufacturing Execution System): MES
Enterprise Automation Level 4 (Management Level): ERP (Enterprise Resource Planning)
Latest Industrial Automation Technology: Industrial Computer Network Control System
