Into a modern production workshop, you may not see groups of workers, instead of rows
of mechanical arms waving accurately, automated conveyor lines running in an orderly manner,
the central control room of the screen in real time jumping with a variety of data. Behind all this
efficient and precise operation, it is industrial automation technology at work. For the manufacturing
industry, understanding the basics of automation is like mastering the universal language that
drives modern industrial production.
What is industrial automation?
Simply put, industrial automation refers to the use of control systems (such as PLC, DCS) and information
technology, so that the industrial production process equipment, processes can be less or no direct human
intervention, according to the preset procedures for automatic operation, detection, control and management.
Its core objective is to achieve “stable, accurate, fast” - that is, stable production, accurate control, fast response,
and ultimately achieve the purpose of improving production efficiency, ensuring product quality, reducing
energy consumption and costs, and enhancing production safety.
A typical automation system usually contains the following three core layers, constituting a
classic “pyramid” structure:
1. Field Layer: Sensing and Execution
This is the “hands and feet” and “senses” of the automation system, which is in direct contact with the
production equipment and the environment. It consists mainly of:
Sensors: as the system's “eyes” and “ears”, responsible for detecting a variety of signals in the physical world, such
as temperature, pressure, flow, position, photoelectric signals, etc., and convert them into electrical signals. For
example, a photoelectric sensor can detect whether the product is in place.
Actuator: Receive control signals to directly drive the device action, is the “hands” and “feet” of the system. The most
common actuators are motors (drive pumps, fans, conveyor belts), in addition to pneumatic/hydraulic cylinders,
solenoid valves, manipulators and so on.
2. Control layer: brain and nerve center
This is the “brain” of the automation system, responsible for processing information and making decisions.
The core equipment is:
Programmable Logic Controller (PLC): industrial automation in the most core, the most widely used control equipment.
It is designed for industrial environments, high reliability, anti-interference ability. PLC cycle execution of user-written
control programs (commonly used ladder language), according to input signals read from the sensor, logical judgment
and mathematical operations, and then send control commands to the actuator. It is the mainstay for realizing discrete
control (e.g., assembly lines, packaging machinery).
Distributed Control System (DCS): It is more suitable for process industries (e.g. chemical, petroleum, pharmaceutical) and
is responsible for centralized monitoring, operation and management of continuous production processes (e.g. PID
regulation of temperature and pressure).
Distributed Control System (DCS): more suitable for process industries (e.g. chemical, petroleum, pharmaceutical).
3. Monitoring Layer: Management and Interaction
This layer is the window for human-system interaction, responsible for data visualization, status monitoring and
production management.
Human-machine interface (HMI): usually a touch screen installed in the workshop site, through which the operator can
check the status of equipment, process parameters, alarm information, and manual operation (such as start, stop).
Data Acquisition and Monitoring System (SCADA): A monitoring system with a wider coverage that can connect
multiple PLCs or DCSs to collect data from sites scattered in different geographic locations for centralized
monitoring, data analysis, historical records and report generation.
The “Language” of Automation Systems: From Hard Wiring to Soft Logic
To understand automation, you must understand signals and logic.
Signal types: mainly divided into digital (switching signals, only 0/1, on/off two states, such as buttons, limit switches)
and analog (continuously changing signals, such as temperature transmitter output 4-20mA current signal, representing
a temperature range).
Realization of control logic: Early automation relied on hard-wired logic (also known as relay logic), where logic functions
were realized through the wiring of physical components such as relays, contactors, etc., and hardware wiring had to be
altered to modify the logic. Modern automation relies mainly on PLC programming, through the software (such as ladder
diagrams, function block diagrams) to define the control logic, flexible modification, powerful. The language notation of
ladder diagrams is derived from relay logic, which allows electrical engineers to easily transition to PLC programming.
Trends in Industrial Automation
Today's industrial automation has long since moved beyond stand-alone automation and is moving in the direction of
integration and intelligence:
Industrial Internet of Things (IIoT): connecting devices and sensors at the field level through a network to realize massive
data collection and cloud aggregation.
Digital Twin: creating a virtual model in the computer that is exactly the same as the physical shop floor, which can be
simulated, debugged and optimized before being put into actual production, dramatically reducing the cost of trial and error.
Artificial Intelligence and Big Data Analytics: using AI algorithms to analyze production data for predictive maintenance
(early warning of equipment failures before they occur), quality optimization, and energy management.
The importance of mastering the basics
For companies, a solid foundation in automation is the path towards smart manufacturing. For practitioners (whether
engineers, technicians or managers), a deep understanding of the basic concepts of sensors, PLCs, and network
communications is like having a screwdriver and a multimeter for analyzing and solving problems. When equipment
failure occurs, you can systematically determine whether it is a sensor signal abnormality, or PLC program logic error,
or network communication interruption, so as to quickly locate and solve the problem.
Conclusion
Industrial automation is a large and sophisticated ecosystem, from a small sensor to the intelligent management of the
entire factory, interlocked. Understanding its fundamentals not only helps us to better operate and maintain existing
systems, but also serves as a cornerstone of our mindset to embrace a smarter, more flexible manufacturing model for
the future. In this era of rapid technological iteration, return to the basics, in order to see the future.