Automated Packaging Solutions in the Era of Industry 4.0

The automated packaging system can significantly improve production efficiency and reduce labor costs. This article provides a detailed introduction to the packaging control system design based on Siemens S7-1200 PLC, helping you grasp the core technical points.

1. Hardware Configuration Plan

PLC and Expansion Module Selection

• • Main Controller: Siemens S7-1200 CPU 1214C DC/DC/DC

• • Digital Expansion: SM 1223 DC/DC 16-point input/16-point output

• • Analog Expansion: SM 1234 4AI/2AO

• • Communication Module: CM 1241 RS485

Selection Basis: The system requires 32 digital inputs, 24 digital outputs, 4 analog inputs (sensors), and 2 analog outputs (inverters).

I/O Point Assignment Table (Partial Example)

Digital Inputs:

%I0.0 - System Start Button

%I0.1 - System Stop Button

%I0.2 - Emergency Stop Button

%I0.3 - Packaging Material Detection

%I0.4 - Packaging Position Detection

...

Digital Outputs:

%Q0.0 - Conveyor Start

%Q0.1 - Packaging Machine Start

%Q0.2 - Warning Light

%Q0.3 - Electromagnetic Valve 1 Control

...

Analog Inputs:

%IW64 - Tension Detection

%IW66 - Temperature Detection

...

2. Control Program Design

A. Variable Definition Specification

Global variable table design (partial example):

DB_System_Para    - System Parameter Data Block

DB_Runtime_Data   - Runtime Data Data Block

DB_Alarm_Info     - Alarm Information Data Block

M_System_Status   - System Status Byte

T_Delay_Start     - Start Delay Timer

C_Package_Count   - Packaging Counter

B. Program Architecture Design

1. 1. System Initialization (OB100)

// Power-on initialization program block

ORGANIZATION_BLOCK "Init"

BEGIN

    // System parameter initialization

    CALL "SYS_Init"
    
    // Device status initialization

    CALL "Device_Init"
    
    // Communication initialization

    CALL "Comm_Init"
END_ORGANIZATION_BLOCK

1. 2. Main Control Program (OB1)

// Main loop program block

ORGANIZATION_BLOCK "Main"

BEGIN

    // System status detection

    CALL "Status_Check"
    
    // Operating mode control

    CALL "Mode_Control"
    
    // Packaging process control

    CALL "Package_Control"
    
    // Data recording processing

    CALL "Data_Record"
END_ORGANIZATION_BLOCK

C. Function Block Design

Taking the packaging control function block as an example:

FUNCTION_BLOCK "Package_Control"

VAR_INPUT

    Start_Command : Bool;    // Start Command

    Stop_Command : Bool;     // Stop Command

    Material_Ready : Bool;   // Material Ready

END_VAR


VAR_OUTPUT

    Running_Status : Bool;   // Running Status

    Error_Code : Int;       // Error Code

END_VAR


VAR

    Step : Int;             // Step Control

    Timer_Delay : Time;     // Delay Control

END_VAR


BEGIN

    // Step control logic

    CASE Step OF

        0:  // Standby State

            IF Start_Command AND Material_Ready THEN

                Step := 10;

            END_IF;
            

        10: // Start Conveyor

            Running_Status := TRUE;

            IF Material_Ready THEN

                Step := 20;

            END_IF;
            

        20: // Execute Packaging

            // Packaging logic implementation

            ...

    END_CASE;
END_FUNCTION_BLOCK

3. Operation Interface Design

The operation interface designed based on WinCC includes the following functional areas:

1. 1. System Operating Status Display

2. 2. Parameter Setting Interface

3. 3. Production Data Statistics

4. 4. Alarm Information Display

Special emphasis is placed on the parameter setting interface, which includes:

• • Packaging Speed Setting

• • Temperature Control Parameters

• • Tension Control Parameters

• • Counter Settings

4. System Debugging Methods

System debugging adopts a step-by-step promotion strategy:

1. 1. I/O Point Testing

• • Test input and output signals one by one

• • Confirm wiring correctness

• • Verify signal quality

1. 2. Individual Function Debugging

• • Conveyor Control Testing

• • Packaging Mechanism Testing

• • Temperature Control System Testing

1. 3. Interlock Testing

• • No-load operation testing

• • Load testing

• • Exception handling testing

5. Experience Summary

1. 1. Debugging Key Points

• • First single machine, then interlock

• • First manual, then automatic

• • First no-load, then load

1. 2. Optimization Suggestions

• • Add predictive maintenance functions

• • Optimize energy consumption management

• • Add data statistical analysis

1. 3. Precautions

• • Ensure electrical isolation

• • Pay attention to EMC design

• • Reserve expansion interfaces

This article provides a detailed introduction to the design and implementation plan of the automated packaging system. We welcome you to share your practical experience and technical questions in the comments section, so we can discuss optimization plans together.