Guangzhou Hengmeida Automation Technology Co., Ltd

In the water treatment industry, RO (reverse osmosis) systems are the key component for producing pure water. Behind the entire system operates a “silent commander”—the PLC (Programmable Logic Controller). It serves as the core control unit and “brain” of the RO system, ensuring stable, efficient, and safe operation throughout the process.   I. Core Functions of PLC The RO system comprises multiple devices, including raw water pumps, chemical dosing systems, high-pressure pumps, membrane modules, conductivity meters, and pressure sensors, all requiring multi-point coordination during operation. The primary task of the PLC is centralized control and logical interlocking of these devices. Through input ports, the PLC continuously collects various signals: - Liquid level signals: Monitor water levels in raw water tanks and product water tanks; Pressure signals: Assessing high-pressure pump operational status and safety thresholds; Conductivity signals: Verifying water quality compliance. Output ports issue control commands based on logical evaluations—such as pump start/stop, valve actuation, chemical dosing, backwashing, and flushing—enabling automated operation without frequent manual intervention.     II. Intelligent Interlocking and Safety Protection PLC control extends beyond simple “on/off commands” to encompass critical logical decision-making and protective mechanisms. When the system detects low water levels in the raw water tank, full production tanks, excessively low inlet pressure, or excessive product water conductivity, the PLC immediately executes shutdown or alarm commands to prevent equipment damage or water quality abnormalities. Simultaneously, during different operational phases (startup, flushing, production, shutdown), the PLC automatically switches control logic to achieve full-process automation, significantly enhancing system reliability and consistency.   III. Remote Monitoring and Data Management With intelligent development, modern PLCs are often connected to host computers or touchscreens (HMI), and may even integrate into building or plant-wide central monitoring systems (SCADA). Operators can view real-time parameters such as flow rate, pressure, and conductivity via HMI, remotely adjust setpoints, or review historical operational data. This enables more intelligent and visual operation and maintenance of RO systems.     IV. Case Study: Industrial Pure Water System Application In the pure water preparation project for Heyue Beverage Factory, the design team employed a Siemens S7-1200 PLC to control the entire RO system. The system comprises raw water chemical dosing, high-pressure pump sets, primary and secondary RO units, product water storage tanks, and concentrate recovery units. The PLC communicates with conductivity meters, flow meters, and variable frequency drives via Modbus protocol to perform the following functions: Automatically determines raw water tank level to trigger raw water pump start/stop; Adjusts backwash frequency based on product water conductivity; Automatically uploads fault alarms (e.g., high-pressure overload, low-pressure protection, membrane blockage) to HMI; Supports remote monitoring via Ethernet connection to the central control room, enabling unattended operation. Application results show a 15% increase in water savings, significantly improved operational stability, and a 50% reduction in manual inspection frequency.   Conclusion: In RO reverse osmosis systems, the PLC serves not merely as a “controller,” but as the ‘brain’ and “guardian” of the entire system. It enables automated equipment coordination, safety protection, and remote management, making pure water production more efficient, stable, and intelligent. Looking ahead, with the integration of IoT and smart manufacturing, PLCs will continue to play an increasingly vital role in water treatment automation.

Components Siemens S7 - 200 SMART PLC + Fanyi Touch Screen + FBox IoT Module + ABB Inverter Core Advantages Unmanned & Fully Automatic Operation Remote Monitoring via Mobile & Computer Fault Alarms with SMS Alerts – Effortless & Efficient Core Functions 1. Self - Diagnostic & Cost Reduction The built - in self - diagnostic function minimizes manual on - site inspections, directly lowering O&M labor costs. 2. Automated Control System Precise Logic Control: Leverages the Siemens S7 - 200 SMART PLC for stable, high - precision logic control, ensuring the smooth operation of pump units under various sewage conditions. Energy - Efficient Speed Regulation: The ABB Inverter dynamically adjusts the motor speed based on real - time sewage level feedback. This “on - demand operation” improves efficiency while cutting unnecessary energy waste. Intuitive On - Site Management: The Fanyi Touch Screen (HMI) provides a visual, user - friendly interface for on - site staff to monitor operations and adjust parameters (e.g., speed, pressure thresholds) intuitively. 3. Remote Monitoring & IoT Integration Cloud - Connected Data Transmission: The FBox IoT Module enables real - time data sync to cloud platforms, supporting remote access via PC/web or mobile apps. Anywhere, Anytime Oversight: Operators can check the pump status (running/stopped), real - time flow rates, historical fault logs, etc., from any location. Timely intervention is guaranteed even off - site. 4. Intelligent Alarm System Multi - Fault Detection: Automatically identifies anomalies such as pump blockages, power outages, or high water levels. Instant SMS Alerts: Triggers immediate SMS notifications to maintenance teams upon fault detection, minimizing downtime and preventing sewage overflow risks. 5. Energy - Saving & Low Maintenance ABB Inverter Efficiency: By optimizing the pump speed to match actual sewage loads, the power consumption is reduced by 20–30% compared to traditional fixed - speed systems. Low Wear & Tear: Smooth speed adjustments reduce mechanical shocks on pumps/motors, extending component lifespans and cutting long - term maintenance costs.

Healthcare Facility Project: Shenzhen Nanshan Hospital PLC Control Cabinets in Hospital Applications: Critical Functions & Implementations Core Application Scenarios A. Life Support Systems Medical Gas Control Function: Regulates the pressures of oxygen (O2​), nitrous oxide (N2​O), and vacuum systems within the range of 0.4–0.55 MPa, ensuring pressure fluctuations remain below 1%. PLC Role: Monitors pipeline pressures using analog input signals (4 - 20 mA). Triggers alarms if pressure thresholds (as specified in EN ISO 7396 - 1) are violated. Safety: Enables automatic shutoff during fire alarms to comply with NFPA 99 standards. HVAC for OR/ICU Precision Control: Maintains air cleanliness at ISO Class 5, with temperature ranging from 20 - 24 °C and relative humidity (RH) between 40 - 60%. PLC Logic: Implements variable frequency drive (VFD) - driven laminar flow control, maintaining air velocity at 0.25 - 0.35 m/s. Monitors differential pressure (DP) of HEPA filters. B. Power Management Critical Load Transfer Implementation: Automatically starts the genset within less than 10 seconds when a grid failure occurs, in line with UL 1008 requirements. PLC Logic: Utilizes a dual - source automatic transfer switch (ATS) with closed - transition switching. Harmonic Mitigation Solution: PLC - controlled active filters reduce harmonics generated by MRI and CT equipment to less than 5% total harmonic distortion (THD). C. Laboratory Automation Biosafety Cabinets Control: Maintains a face velocity of 0.5 m/s while dynamically adjusting the sash position. Data Logging: Stores operation records that comply with 21 CFR Part 11. Specialized Control Requirements EMC Considerations Shielding Enclosures compliant with MIL - STD - 461G are used in MRI zones to ensure electromagnetic compatibility (EMC). Noise Immunity Optical isolation is employed for ECG/EEG equipment to meet IEC 60601 - 1 - 2 noise immunity requirements. Redundancy Design Architecture Uses dual hot - standby CPUs (SIL 3) for dialysis machines to ensure operational continuity. Failsafe Incorporates watchdog timers with a failover time of less than 100 ms. Operational Benefits Patient Safety Prevents errors in the mixing of anesthetic gases through interlocked valve control. Energy Efficiency Achieves a 30% reduction in HVAC energy consumption through occupancy - based ventilation strategies. Maintenance Optimization Employs predictive algorithms to detect pump bearing wear via vibration fast Fourier transform (FFT) analysis. Implementation Examples Department PLC Model Key I/O Configuration OR Suites Siemens S7 - 1500 16 AI (PT100), 32 DO (24 VDC) Pharmacy Allen - Bradley CompactLogix 8 - axis servo control Central Sterile Omron NJ501 EtherCAT - connected SCARA robots