Design and Practice of Industrial Pressure Control System

Design and Practice of Industrial Pressure Control System

Part One: Application Overview In modern industrial production, precise pressure control is key to ensuring product quality and production safety. This article will detail the design of an industrial pressure monitoring and control system based on the Siemens S7-1200 PLC. This project is suitable for beginners in electrical automation and industrial control, helping them grasp PLC programming and industrial control system development skills, laying a solid foundation for future industrial automation engineers.

Part Two: Hardware Configuration Hardware List:

1. Siemens S7-1200 PLC Main Unit CPU 1214C
2. Analog Input Module SM 1231 (4-channel analog input)
3. Pressure Sensor SIEMENS SITRANS P240
4. Solenoid Valve 24VDC
5. Power Module PM1207 AC/DC
6. Terminal Blocks and Wires

Hardware Connection Diagram:

Pressure Sensor -> Analog Input Module -> PLC Main Unit -> Solenoid Valve Control

Part Three: Program Design Ideas Core Process of the Control System:

1. Collect analog signal from pressure sensor
2. Signal linearization and calibration
3. Pressure threshold judgment
4. Solenoid valve switch control
5. Data recording and alarm

Program Flowchart:

[Pressure Collection] -> [Signal Processing] -> [Threshold Comparison] -> [Valve Control] -> [Data Recording]

Key Technical Points:

• Analog Signal Processing
• PID Control Algorithm
• Real-time Data Monitoring
• Abnormal State Management

Part Four: Program Code Implementation

FUNCTION_BLOCK PressureControlVAR_INPUT    ActualPressure : REAL;    // Actual pressure value    SetPressure : REAL;       // Set pressure value    DeadBand : REAL;          // Deadband rangeEND_VARVAR_OUTPUT    ValveState : BOOL;        // Solenoid valve stateEND_VARBEGIN    // Pressure control logic    IF ActualPressure < (SetPressure - DeadBand) THEN        ValveState := TRUE;   // Open valve    ELSIF ActualPressure > (SetPressure + DeadBand) THEN        ValveState := FALSE;  // Close valve    END_IF;END_FUNCTION_BLOCK

Part Five: Debugging Methods Common Problems and Solutions:

1. Unstable signal:

* Check wiring* Increase signal filtering* Shield against electromagnetic interference

1. Sensor accuracy issues:

* Regular calibration* Use high-precision sensors* Software compensation algorithms

Debugging Steps:

• Check hardware connections
• Signal linearization
• Threshold parameter tuning
• Real-time monitoring and recording

Part Six: Function Expansion Expandable Features:

• Remote Monitoring
• Data Recording and Analysis
• Multi-point Pressure Control
• Intelligent Early Warning System

Application Areas:

• Chemical Process Control
• Air Compressor Systems
• Hydraulic Equipment
• Pharmaceutical Production Lines

Part Seven: Conclusion This project demonstrates the application of PLC in industrial pressure control through practice. By systematically designing the control system, readers can gain a deeper understanding of the basic principles and methods of industrial automation. Being proactive and continuously practicing is key to becoming an excellent engineer.

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