Automated Assembly Line for Automotive

PROGRAM ASSEMBLY_LINE_STATION_CONTROL
VAR
    // Station Sensors
    station1_part_present : BOOL;
    station2_part_present : BOOL;
    station3_part_present : BOOL;
    operation_complete : ARRAY[1..3] OF BOOL;

    // Outputs
    conveyor_move : BOOL;
    station_clamp : ARRAY[1..3] OF BOOL;
    station_tool : ARRAY[1..3] OF BOOL;

    // State Machine
    state : INT := 0;  // 0=Wait, 1=Process, 2=Transfer
    timer : INT := 0;

    // Operation Times (100ms cycles)
    OPERATION_TIME : ARRAY[1..3] OF INT := [50, 80, 60];
    TRANSFER_TIME : INT := 20;

    // Part Tracking
    parts_completed : INT := 0;
    cycle_time : INT := 0;


    // Production Metrics
    Takt_Time : TIME := T#60s;  // Target time per unit
    Cycle_Start_Time : TIME;
    Actual_Cycle_Time : TIME;
    Cycle_Time_OK : BOOL;

    // OEE (Overall Equipment Effectiveness) Tracking
    Availability_Percent : REAL;
    Performance_Percent : REAL;
    Quality_Percent : REAL;
    OEE_Percent : REAL;

    // Production Counters
    Units_Produced_Shift : INT := 0;
    Good_Parts_Count : INT := 0;
    Reject_Parts_Count : INT := 0;
    Rework_Parts_Count : INT := 0;

    // Downtime Tracking
    Downtime_Seconds : INT := 0;
    Downtime_Reason : STRING[50];
    Last_Downtime_Start : DATE_AND_TIME;

    // Andon System
    Andon_Status : INT;  // 0=Green, 1=Yellow, 2=Red
    Line_Stop_Request : BOOL;
    Material_Shortage : BOOL;
    Quality_Issue : BOOL;
    Maintenance_Required : BOOL;

    // Just-In-Time Integration
    Upstream_Buffer_Count : INT;
    Downstream_Buffer_Count : INT;
    Material_Call_Signal : BOOL;

    // Quality Gates
    Vision_Inspection_Pass : BOOL;
    Torque_Verification_Pass : BOOL;
    Dimension_Check_Pass : BOOL;
    All_Quality_Checks_Pass : BOOL;
END_VAR

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

timer := timer + 1;
cycle_time := cycle_time + 1;

CASE state OF
    0: // Wait for all stations ready
        conveyor_move := FALSE;

        // Check if all stations have parts and completed previous operation
        IF station1_part_present AND station2_part_present AND
           station3_part_present THEN
            state := 1;
            timer := 0;
            // Clamp all parts
            station_clamp[1] := TRUE;
            station_clamp[2] := TRUE;
            station_clamp[3] := TRUE;
        END_IF;

    1: // Process all stations simultaneously
        // Activate tools based on timer
        FOR i := 1 TO 3 DO
            IF timer < OPERATION_TIME[i] THEN
                station_tool[i] := TRUE;
            ELSE
                station_tool[i] := FALSE;
                operation_complete[i] := TRUE;
            END_IF;
        END_FOR;

        // When all operations complete
        IF operation_complete[1] AND operation_complete[2] AND
           operation_complete[3] THEN
            state := 2;
            timer := 0;
            // Release clamps
            station_clamp[1] := FALSE;
            station_clamp[2] := FALSE;
            station_clamp[3] := FALSE;
        END_IF;

    2: // Transfer parts to next station
        conveyor_move := TRUE;

        IF timer > TRANSFER_TIME THEN
            state := 0;
            timer := 0;
            parts_completed := parts_completed + 1;
            cycle_time := 0;  // Reset for next cycle

            // Reset operation flags
            operation_complete[1] := FALSE;
            operation_complete[2] := FALSE;
            operation_complete[3] := FALSE;
        END_IF;
END_CASE;

// ==========================================
// AUTOMOTIVE SPECIFIC LOGIC
// ==========================================

    // Takt Time Monitoring for Lean Production
    IF Cycle_State = CYCLE_START THEN
        Cycle_Start_Time := CURRENT_TIME();
    ELSIF Cycle_State = CYCLE_COMPLETE THEN
        Actual_Cycle_Time := CURRENT_TIME() - Cycle_Start_Time;
        Cycle_Time_OK := (Actual_Cycle_Time <= Takt_Time);

        IF NOT Cycle_Time_OK THEN
            Andon_Status := 1;  // Yellow - Behind takt
        END_IF;
    END_IF;

    // OEE Calculation
    // Availability = (Operating Time - Downtime) / Operating Time
    Availability_Percent := ((Shift_Time - Downtime_Seconds) / Shift_Time) * 100.0;

    // Performance = (Actual Production / Target Production) * 100
    Performance_Percent := (Units_Produced_Shift / Target_Units_Shift) * 100.0;

    // Quality = (Good Parts / Total Parts) * 100
    IF Units_Produced_Shift > 0 THEN
        Quality_Percent := (Good_Parts_Count / Units_Produced_Shift) * 100.0;
    END_IF;

    // OEE = Availability × Performance × Quality
    OEE_Percent := (Availability_Percent * Performance_Percent * Quality_Percent) / 10000.0;

    // Andon Board Control - Visual Management
    IF Emergency_Stop OR Critical_Fault THEN
        Andon_Status := 2;  // Red - Line stop
        Downtime_Reason := 'EMERGENCY_STOP';

    ELSIF Material_Shortage THEN
        Andon_Status := 2;  // Red - Material needed
        Line_Stop_Request := TRUE;
        Downtime_Reason := 'MATERIAL_SHORTAGE';

    ELSIF Quality_Issue THEN
        Andon_Status := 1;  // Yellow - Quality alert
        Downtime_Reason := 'QUALITY_ISSUE';

    ELSIF Maintenance_Required THEN
        Andon_Status := 1;  // Yellow - Maintenance needed

    ELSE
        Andon_Status := 0;  // Green - Normal operation
    END_IF;

    // Just-In-Time Material Pull System
    IF Upstream_Buffer_Count < Min_Buffer_Level THEN
        Material_Call_Signal := TRUE;
        // Signal upstream process to send material
    END_IF;

    IF Downstream_Buffer_Count > Max_Buffer_Level THEN
        Production_Enable := FALSE;
        // Stop production to prevent overproduction (muda)
    END_IF;

    // Quality Gate Verification
    All_Quality_Checks_Pass := Vision_Inspection_Pass
                               AND Torque_Verification_Pass
                               AND Dimension_Check_Pass;

    IF NOT All_Quality_Checks_Pass THEN
        Reject_Parts_Count := Reject_Parts_Count + 1;
        Quality_Issue := TRUE;
        // Activate reject station
    ELSE
        Good_Parts_Count := Good_Parts_Count + 1;
    END_IF;

    Units_Produced_Shift := Good_Parts_Count + Reject_Parts_Count;

// ==========================================
// AUTOMOTIVE SAFETY INTERLOCKS
// ==========================================

    // Production Enable Conditions
    Production_Allowed := NOT Line_Stop_Request
                          AND NOT Material_Shortage
                          AND (Andon_Status <> 2)
                          AND (Downstream_Buffer_Count < Max_Buffer_Level)
                          AND NOT Emergency_Stop;

    // Quality Interlock
    IF NOT All_Quality_Checks_Pass THEN
        // Part routed to reject bin automatically
        Part_Accept_Gate := FALSE;
        Part_Reject_Gate := TRUE;
    END_IF;

    // Cycle Time Violation Alert
    IF Actual_Cycle_Time > (Takt_Time * 1.1) THEN
        // 10% over takt time triggers investigation
        Cycle_Time_Alarm := TRUE;
    END_IF;