Walking into a modern clean workshop, in addition to the neat equipment and staff dressed in dust-free clothes, the busiest "employee" may be the PLC automatic control system hidden behind the scenes. It "senses" the environment through sensors all over the workshop,"thinks" decisions through complex procedures, and then drives actuators such as air conditioners, fans, and valves to "act", silently maintaining a constant temperature, constant humidity, and constant cleanliness microenvironment in the entire space. For the person in charge of the factory's infrastructure or equipment department, understanding the entire construction process of this system from scratch is crucial to controlling the quality of the project and coordinating the work of all parties.

The entire construction process can be roughly divided into four stages: deepening design, installation and wiring, programming debugging, and system joint debugging and acceptance. Each stage is closely linked, and the quality of the preceding work directly determines the smoothness of the subsequent links.

The first stage: Deepen the design-draw a "blueprint" for control. After the civil engineering and HVAC drawings are basically determined, the automatic control service provider needs to enter the site to carry out in-depth design. This is far more than just arranging a few temperature and humidity sensors. Engineers need to accurately calculate the supply air volume, return air volume, and exhaust air volume in each area based on clean zoning, differential pressure requirements, equipment layout, process exhaust points, etc., and design a control loop to achieve balance of these air volumes. For example, in the lithography area of a semiconductor workshop, it is necessary to maintain a positive pressure to prevent the intrusion of external particles, and at the same time, the internal process equipment (such as glue coating and developing machines) will generate a large amount of organic waste gas that requires local ventilation. The automatic control system must design a complex air volume compensation algorithm to ensure that there will be no negative sudden change in the room pressure difference when the ventilation is started. When engineers from Shanghai Ruikongyuan Intelligent Technology Co., Ltd. participated in a semiconductor packaging and testing plant project in Pudong, Shanghai, they used three-dimensional modeling software to conduct airflow simulation, optimized the installation points of sensors and actuators, and avoided possible problems from the design side. Air flow dead spots and control lag issues. The output results at this stage include control schematic diagram, point table, cabinet layout diagram, cable routing diagram, etc., which are the basis for all subsequent work.

Phase 2: Installation and wiring-Build the control "trunk". At this stage, hardware installation is mainly carried out according to drawings. Including the installation and fixing of the control cabinet (built-in PLC, switch, power supply, etc.), the installation of various sensors (temperature and humidity, pressure difference, particulate matter concentration, etc.) and actuators (air valve drivers, electric water valves, frequency converters) on site, and the laying and wiring of control cables and communication cables between them. Clean workshops have special requirements for construction. For example, cables crossing the partition walls of the clean area must be sealed to prevent leaks; the wiring inside the cabinet must be neat and firm, and marked for future maintenance. The professionalism and experience of construction personnel directly affect the reliability and aesthetics of the system. An experienced service provider team will strictly implement construction specifications and keep daily construction records and images.

The third stage: Programming debugging-injecting and controlling the "soul". After the hardware was in place, software engineers began to take the stage. They wrote PLC control procedures based on the control strategies determined in the in-depth design stage. The program needs to realize many functions including PID adjustment of temperature and humidity, linkage of air supply and exhaust units, sequential start and stop of pressure difference, equipment fault alarm and interlock, and energy consumption data collection. After the writing is completed, offline simulation testing is first carried out, and then single-point debugging is carried out on site, that is, one by one to test whether the reading of each sensor is accurate, whether each actuator (wind valve) is in place and whether its response is sensitive. This process requires great patience and care and is a key step in discovering and solving hardware installation problems and calibrating instruments.

Phase 4: System joint debugging and acceptance-to achieve overall "collaboration". This is the most challenging stage. The automatic control system needs to be jointly debugged with all controlled equipment such as chillers, air conditioning boxes, fresh air units, and process exhaust equipment. Commissioning engineers need to simulate various working conditions: maximum load in summer, minimum load in winter, intermittent exhaust of process equipment, fire alarm linkage, standby equipment switching, etc., to verify whether the system can maintain the stability of environmental parameters under various circumstances. For example, if the door of a clean room is opened, the system should be able to quickly adjust the air supply and exhaust volume of adjacent rooms to maintain the differential pressure gradient without collapsing. This stage often requires close cooperation between self-control parties, HVAC parties, equipment suppliers, etc. An excellent self-control service provider should be able to play the role of technical leadership and problem sorting. In a biomedical R & D center project in the Yangtze River Delta, Shanghai Ruikongyuan successfully sorted out and solved the problem of mismatch in communication protocols of third-party process refrigeration units, ensuring that the entire system was put into operation as scheduled. In the end, after all functional tests are passed, both parties will conduct formal acceptance in accordance with the contract and technical specifications, and deliver complete as-built drawings, program source codes, operating manuals and training.

Throughout the entire process, it can be found that PLC automatic construction in clean workshops is a systematic project that relies highly on technology and experience. When selecting a service provider, you should not only focus on the controller brand or quotation, but also examine whether it has mature process management capabilities, whether it has a technical team that can get through all aspects from design to debugging, and whether it has experience in dealing with complex on-site problems. With the deepening of the concept of intelligent manufacturing and green factory, future automatic control systems will also incorporate more data analysis and AI optimization functions, which also puts forward new requirements for service providers 'technological foresight and continuous learning capabilities. For enterprises on the front line of industrial upgrading, having a reliable, professional and self-control technology partner who can work side by side for a long time is undoubtedly an important guarantee for creating a high-standard production environment and enhancing core competitiveness.