Why centralized control of FFU?

In high-end manufacturing fields such as semiconductor wafer manufacturing, panel display, and biopharmaceuticals, clean rooms usually require the deployment of hundreds or even thousands of FFU (fan filter units). If each FFU operates independently and is adjusted manually, it will face three outstanding problems:

• Low management efficiency : Manual speed adjustment and inspection of hundreds of FFUs one by one is huge and unrealistic.

• High energy consumption costs : all FFUs run at full speed and the electricity bill is staggering

• It is difficult to ensure cleanliness : FFU wind speeds in various areas are inconsistent, which may lead to uneven air flow or local eddy currents.

FFU centralized control (also known as group control system) was born to solve these problems - connect a large number of FFU to a unified management platform to achieve centralized monitoring, remote speed adjustment, automatic adjustment and fault warning.

The composition of FFU centralized control system

A complete FFU centralized control system usually contains the following levels:

Central management layer : A PC or touch screen deployed in the central control room installs central management software to monitor the running status of all FFUs, set speed strategies, and receive fault alarms.

Communication network layer : The bus system responsible for data transmission uses mature industrial fieldbus technology to ensure real-time and reliable data transmission. There are also systems that use wireless communication technology, which can significantly reduce the workload of on-site wiring.

Regional control layer : Divide FFU into several control groups, each group is managed by a partition controller (usually each controller manages 16-32 FFU). Each zone controller can work independently, and a single fault will not affect other zones.

Terminal execution layer : Each FFU is equipped with an intelligent drive board, which receives speed instructions and feeds back operating status (start and stop, speed, current, fault alarm, etc.).

Three architecture types of FFU control systems

According to different control methods, the FFU control system can be divided into the following three architectures:

1. Independent control system (single machine control)

Each FFU is equipped with an independent controller (such as a potentiometer knob or digital speed regulator), and users need to manually adjust the wind speed one by one. The advantages are low initial cost, simple installation, and failure of a single unit does not affect other equipment. The disadvantage is that it cannot be managed centrally and is not suitable for large-scale clean rooms.

2. Centralized control system

All FFUs in a designated area are connected to a central control cabinet, and the speed of all FFUs is adjusted simultaneously through the main controller. The advantages are unified control and simplified operation. The disadvantage is the risk of a single point of failure - failure of the central controller can bring down the entire system, and limited scalability.

3. Networked (intelligent) control system

Each FFU is equipped with an intelligent controller (usually with an EC motor) and a unique network address, and is connected to the central management PC through the communication network. This is currently the most advanced architecture for large clean rooms. Its advantages include: supporting group control, regional control and even independent adjustment of a single unit; real-time monitoring of wind speed, motor status, filter pressure difference, alarm status and other data of each FFU; supporting on-demand speed adjustment, with significant energy saving effect; flexible system expansion, and the failure of a single controller will not affect the entire network.

The core control strategy of FFU centralized control

Strategy 1: Partition speed control

Different areas have different requirements for cleanliness, and the FFU speed should also be different. The core process area (such as ISO level 5) can maintain a rotation speed of 90%-100%, the general production area (ISO level 6) is set to 60%-80%, and the corridor and auxiliary area (ISO level 7) is set to 40%-60%.

Strategy 2: Period adjustment

Dynamically adjust the FFU speed according to the production rhythm. The production period runs normally according to the zone setting; the shift gap can be reduced by 20%-30%; the minimum speed is maintained at night or on holidays to prevent the cleanliness from declining; it runs at full speed for 20-30 minutes before starting up to quickly self-clean.

Strategy 3: Closed-loop control (based on particle monitoring)

Install online particle counters in key areas to automatically adjust the FFU speed based on real-time particle concentration. When the particle number is far below the limit, the speed is reduced to save energy, when the particle number is close to the limit, the speed is increased to ensure safety, and when the particle number exceeds the limit, it runs at full speed and alarms.

Strategy 4: Pressure difference balance control

Based on the feedback from the pressure difference sensors deployed at each test point in the clean area, the FFU fan speed in the corresponding area is dynamically fine-tuned to maintain the positive pressure difference between the clean area and the non-clean area.

Advantages of FFU centralized control

Significant energy savings

Taking a 2,000-square-meter ISO 6 clean room as an example, the annual electricity bill for about 500 FFUs running at full speed is about 800,000 yuan. The average speed is reduced to 70% of the rated speed through the group control system. Since the fan power has a cubic relationship with the speed, the actual power is only 34% of the rated power. The annual electricity bill is reduced to approximately 270,000 yuan, saving 530,000 yuan per year. The investment in a group control system can usually be recovered within 1-2 years through savings in electricity bills.

Improve management efficiency

Operators can view the operating status of all FFUs at a glance in the central control room, enabling remote start and stop, speed adjustment and troubleshooting, significantly reducing the workload of manual inspections.

Extend equipment life

By adjusting the speed on demand, the FFU can be prevented from running at full load for a long time, reducing the wear of fans and motors, and extending the service life of the equipment.

Ensure stable cleanliness

Real-time monitoring and automatic adjustment ensure uniform wind speed and stable pressure difference in each area, and avoid cleanliness fluctuations caused by untimely manual adjustment.

Aili Industry—Full industry chain FFU manufacturer

Aili Industrial has been deeply involved in the field of clean room equipment for nearly two decades. From fan winding, motor research and development to control system development, the entire industry chain independently manufactures FFU fan filter units. The software and hardware of Aili Industrial Intelligent Group Control System are all independently developed , and a single system can control 100,000 FFU/EFU. The system supports multiple control strategies such as partition control, time period adjustment, and pressure difference balance, and can customize control plans according to customer needs. The products cover a full range of FFUs including standard, ultra-thin, energy-saving (EC motor), and group control types, adapting to the different cleaning needs of 13 major industries including semiconductors, panel displays, pharmaceuticals, food, and data centers.

If you need FFU centralized control solution or group control system customization, please contact Aili Industrial’s professional technical team.