Injection Molding Machine for Electronics Manufacturing

PROGRAM PLC_CONTROL_LOGIC_EXAMPLE
VAR
    // Inputs
    start_button : BOOL;
    stop_button : BOOL;
    system_ready : BOOL;
    error_detected : BOOL;

    // Outputs
    motor_run : BOOL;
    alarm_signal : BOOL;

    // Internal State
    system_state : INT := 0; // 0=Idle, 1=Running, 2=Error
    runtime_counter : INT := 0;


    // Cleanroom Control (ESD-Safe Environment)
    Room_Humidity : REAL;      // 30-50% RH for ESD control
    Room_Temperature : REAL;   // Tight tolerance ±1°C
    Particle_Count_0_5um : REAL;
    Cleanroom_Class : STRING[10];  // Class 100, 1000, 10000

    // ESD (Electrostatic Discharge) Protection
    ESD_Wrist_Strap_OK : ARRAY[1..10] OF BOOL;
    Ionizer_Status : BOOL;
    Static_Voltage : REAL;     // Volts
    ESD_Event_Detected : BOOL;

    // SMT (Surface Mount Technology) Line
    Pick_Place_Position_X : REAL;
    Pick_Place_Position_Y : REAL;
    Component_Placement_Count : INT;
    Vision_Inspection_Pass : BOOL;

    // Reflow Oven Profile
    Zone_Temperature : ARRAY[1..7] OF REAL;
    Solder_Profile_Active : STRING[20];  // 'LEAD_FREE', 'LEADED'
    Peak_Temp_Reached : BOOL;
    Time_Above_Liquidus : TIME;

    // AOI (Automated Optical Inspection)
    Defect_Detected : BOOL;
    Defect_Type : STRING[30];
    Solder_Joint_Quality : REAL;  // 0-100%

    // Component Traceability
    PCB_Serial_Number : STRING[20];
    Component_Lot_Codes : ARRAY[1..50] OF STRING[20];
    Board_Revision : STRING[10];
END_VAR

// ==========================================
// BASE APPLICATION LOGIC
// ==========================================

CASE system_state OF
    0: // Idle state
        motor_run := FALSE;
        alarm_signal := FALSE;

        IF start_button AND system_ready AND NOT error_detected THEN
            system_state := 1;
        END_IF;

    1: // Running state
        motor_run := TRUE;
        alarm_signal := FALSE;
        runtime_counter := runtime_counter + 1;

        IF stop_button OR error_detected THEN
            system_state := 2;
        END_IF;

    2: // Error state
        motor_run := FALSE;
        alarm_signal := TRUE;

        IF stop_button AND NOT error_detected THEN
            system_state := 0;
            runtime_counter := 0;
        END_IF;
END_CASE;

// ==========================================
// ELECTRONICS MANUFACTURING SPECIFIC LOGIC
// ==========================================

    // Cleanroom Environmental Control
    // Maintain tight humidity range for ESD protection
    IF Room_Humidity < 30.0 THEN
        Humidifier_Active := TRUE;
        ESD_Risk := TRUE;  // Low humidity increases static
    ELSIF Room_Humidity > 50.0 THEN
        Dehumidifier_Active := TRUE;
        Corrosion_Risk := TRUE;  // High humidity causes corrosion
    ELSE
        ESD_Risk := FALSE;
        Corrosion_Risk := FALSE;
    END_IF;

    // Particle Count Monitoring for Cleanroom Classification
    IF Particle_Count_0_5um <= 100.0 THEN
        Cleanroom_Class := 'CLASS_100';  // ISO 5
    ELSIF Particle_Count_0_5um <= 1000.0 THEN
        Cleanroom_Class := 'CLASS_1000'; // ISO 6
    ELSIF Particle_Count_0_5um <= 10000.0 THEN
        Cleanroom_Class := 'CLASS_10000'; // ISO 7
    ELSE
        Cleanroom_Class := 'OUT_OF_SPEC';
        Production_Enable := FALSE;
    END_IF;

    // ESD Protection System Monitoring
    FOR i := 1 TO 10 DO
        IF NOT ESD_Wrist_Strap_OK[i] THEN
            // Operator wrist strap disconnected
            Station_Enable[i] := FALSE;
            ESD_Alarm := TRUE;
        END_IF;
    END_FOR;

    // Static voltage monitoring
    IF ABS(Static_Voltage) > 100.0 THEN  // >100V is damaging
        ESD_Event_Detected := TRUE;
        Ionizer_Status := TRUE;  // Activate ionizer
    END_IF;

    // Reflow Oven Temperature Profile Control
    // Lead-free solder profile (SAC305): Peak 245-255°C
    IF Solder_Profile_Active = 'LEAD_FREE' THEN
        Zone_Temperature[1] := 150.0;  // Preheat
        Zone_Temperature[2] := 170.0;
        Zone_Temperature[3] := 190.0;
        Zone_Temperature[4] := 220.0;  // Soak zone
        Zone_Temperature[5] := 240.0;
        Zone_Temperature[6] := 250.0;  // Peak reflow
        Zone_Temperature[7] := 200.0;  // Cooling

        Peak_Reflow_Temp := 250.0;
        Liquidus_Temp := 217.0;  // SAC305 liquidus point
    END_IF;

    // Time Above Liquidus (TAL) monitoring
    // Critical for solder joint quality (60-120 seconds typical)
    IF Zone_Temperature[6] > Liquidus_Temp THEN
        TAL_Timer(IN := TRUE);
        Time_Above_Liquidus := TAL_Timer.ET;

        IF Time_Above_Liquidus > T#120s THEN
            // Excessive time - component damage risk
            Reflow_Profile_Alarm := TRUE;
        END_IF;
    ELSE
        TAL_Timer(IN := FALSE);
    END_IF;

    // AOI Defect Detection
    IF Defect_Detected THEN
        CASE Defect_Type OF
            'MISSING_COMPONENT':
                Reject_Reason := 'COMPONENT_MISSING';
            'SOLDER_BRIDGE':
                Reject_Reason := 'SHORT_CIRCUIT_RISK';
            'INSUFFICIENT_SOLDER':
                Reject_Reason := 'POOR_JOINT';
            'COMPONENT_OFFSET':
                Reject_Reason := 'MISALIGNMENT';
        END_CASE;

        Board_Reject := TRUE;
        Reject_Count := Reject_Count + 1;
    END_IF;

    // Solder Joint Quality Assessment
    IF Solder_Joint_Quality < 80.0 THEN  // <80% quality score
        Board_Rework := TRUE;
        // Send to rework station
    END_IF;

    // Component Traceability Logging
    // Store complete BOM lot codes with PCB serial number
    FOR i := 1 TO 50 DO
        IF Component_Lot_Codes[i] <> '' THEN
            // Log to traceability database
            Log_Component_Traceability(PCB_Serial_Number,
                                       Component_Lot_Codes[i],
                                       Placement_Timestamp);
        END_IF;
    END_FOR;

// ==========================================
// ELECTRONICS MANUFACTURING SAFETY INTERLOCKS
// ==========================================

    // Production Enable Interlocks
    Production_Allowed := (Cleanroom_Class = 'CLASS_100' OR
                          Cleanroom_Class = 'CLASS_1000')
                          AND NOT ESD_Risk
                          AND (Room_Humidity >= 30.0 AND Room_Humidity <= 50.0)
                          AND (Room_Temperature >= 20.0 AND Room_Temperature <= 24.0)
                          AND Ionizer_Status
                          AND NOT ESD_Event_Detected;

    // ESD Protection Interlock
    // Prevent operation if any operator ESD protection failed
    FOR i := 1 TO 10 DO
        IF NOT ESD_Wrist_Strap_OK[i] THEN
            Station_Enable[i] := FALSE;
        END_IF;
    END_FOR;

    // Reflow Oven Safety
    IF Zone_Temperature[6] > Peak_Reflow_Temp + 10.0 THEN
        // Over-temperature - component damage
        Reflow_Oven_Emergency_Stop := TRUE;
        Conveyor_Stop := TRUE;
    END_IF;

    // Cleanroom Environmental Excursion
    IF Particle_Count_0_5um > Cleanroom_Limit THEN
        // Cleanroom compromised
        Production_Enable := FALSE;
        Environmental_Alarm := TRUE;
        // Quarantine all WIP (Work In Progress)
    END_IF;