Conveyor Belt Systems for Manufacturing

PROGRAM CONVEYOR_BELT_VARIABLE_SPEED_CONTROL
VAR
    // Inputs
    emergency_stop : BOOL;
    load_sensor : BOOL;
    upstream_ready : BOOL;
    downstream_ready : BOOL;

    // Analog Inputs
    belt_speed_fb : REAL;  // 0-100% speed feedback
    load_weight : REAL;     // Weight in kg

    // Outputs
    vfd_enable : BOOL;
    vfd_speed_sp : REAL;   // Speed setpoint 0-100%

    // Internal Variables
    target_speed : REAL := 50.0;
    ramp_rate : REAL := 5.0;  // %/second
    overload_limit : REAL := 500.0;  // kg


    // Production Tracking
    Production_Count : INT := 0;
    Target_Production : INT := 1000;
    Production_Rate : REAL;  // Units per hour
    Shift_Start_Time : DATE_AND_TIME;

    // Predictive Maintenance
    Vibration_Level : REAL;  // mm/s RMS
    Bearing_Temperature : REAL;
    Runtime_Hours : REAL;
    Maintenance_Due : BOOL;
    Next_PM_Date : DATE;

    // Energy Monitoring
    Power_Consumption : REAL;  // kW
    Energy_Total_Daily : REAL; // kWh
    Energy_Per_Unit : REAL;    // kWh per part
    Peak_Demand_Alarm : BOOL;

    // Material Tracking
    Material_Batch_ID : STRING[20];
    Material_Quantity : REAL;
    Scrap_Count : INT;
    Scrap_Percentage : REAL;

    // Machine Status
    Machine_State : STRING[20];
    Idle_Time : TIME;
    Run_Time : TIME;
    Utilization_Percent : REAL;
END_VAR

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

// Emergency stop handling
IF NOT emergency_stop THEN
    vfd_enable := FALSE;
    vfd_speed_sp := 0.0;
    RETURN;
END_IF;

// Load-based speed adjustment
IF load_weight > overload_limit THEN
    target_speed := 30.0;  // Reduce speed when overloaded
ELSIF upstream_ready AND downstream_ready THEN
    target_speed := 80.0;  // Full speed when clear
ELSE
    target_speed := 50.0;  // Medium speed otherwise
END_IF;

// Ramp speed setpoint smoothly
IF vfd_speed_sp < target_speed THEN
    vfd_speed_sp := MIN(vfd_speed_sp + (ramp_rate * 0.1), target_speed);
ELSIF vfd_speed_sp > target_speed THEN
    vfd_speed_sp := MAX(vfd_speed_sp - (ramp_rate * 0.1), target_speed);
END_IF;

vfd_enable := TRUE;

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

    // Production Rate Calculation
    Production_Rate := Production_Count / Runtime_Hours;

    // Utilization Tracking
    Utilization_Percent := (Run_Time / (Run_Time + Idle_Time)) * 100.0;

    // Predictive Maintenance Alert
    IF (Vibration_Level > Normal_Vibration * 2.0) OR
       (Bearing_Temperature > Normal_Temp + 20.0) OR
       (Runtime_Hours >= PM_Interval_Hours) THEN
        Maintenance_Due := TRUE;
        Machine_State := 'MAINTENANCE_REQUIRED';
    END_IF;

    // Energy Efficiency Monitoring
    Energy_Per_Unit := Energy_Total_Daily / Production_Count;

    IF Power_Consumption > Peak_Demand_Limit THEN
        Peak_Demand_Alarm := TRUE;
        // Implement load shedding if needed
    END_IF;

    // Scrap Rate Tracking
    Scrap_Percentage := (Scrap_Count / Production_Count) * 100.0;

    IF Scrap_Percentage > Target_Scrap_Percent THEN
        Quality_Alert := TRUE;
    END_IF;

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

    // Production Enable
    Production_Allowed := NOT Maintenance_Due
                          AND (Material_Quantity > Min_Material)
                          AND NOT Emergency_Stop
                          AND NOT Peak_Demand_Alarm;