text: <user>
  Create a function block for temperature control in TwinCAT Structured Text<|endoftext|>
  <assistant>
  FUNCTION_BLOCK FB_TemperatureControl
  VAR_INPUT
      fSetpoint       : REAL;    // Desired temperature setpoint
      fCurrentTemp    : REAL;    // Current temperature reading
      bEnable         : BOOL;    // Enable control
  END_VAR
  VAR_OUTPUT
      fHeaterOutput   : REAL;    // Heater output (0-100%)
      bAlarm          : BOOL;    // Temperature alarm
  END_VAR
  VAR
      fError          : REAL;    // Error between setpoint and current temperature
      fKp             : REAL := 2.0;    // Proportional gain
      fKi             : REAL := 0.1;    // Integral gain
      fIntegral       : REAL;    // Integral term
      fbTON           : TON;     // Timer for integral calculation
      tSampleTime     : TIME := T#100MS;    // Sample time for control loop
  END_VAR
  
  // Main control logic
  IF bEnable THEN
      // Calculate error
      fError := fSetpoint - fCurrentTemp;
      
      // Calculate integral term
      fbTON(IN := TRUE, PT := tSampleTime);
      IF fbTON.Q THEN
          fIntegral := fIntegral + fError * REAL_TO_LREAL(TIME_TO_REAL(tSampleTime)) / 1000.0;
          fbTON(IN := FALSE);
      END_IF
      
      // Calculate PID output
      fHeaterOutput := LIMIT(0.0, fKp * fError + fKi * fIntegral, 100.0);
      
      // Check for alarm condition (temperature too high)
      bAlarm := fCurrentTemp > (fSetpoint + 10.0);
  ELSE
      // Reset outputs when disabled
      fHeaterOutput := 0.0;
      bAlarm := FALSE;
      fIntegral := 0.0;
  END_IF
  
  (* 
  This function block implements a simple PI (Proportional-Integral) temperature controller.
  It calculates the heater output based on the difference between the setpoint and current temperature.
  The control loop runs every 100ms, and the output is limited between 0-100%.
  An alarm is triggered if the temperature exceeds the setpoint by more than 10 degrees.
  *)
  
  // Suggested TwinCAT 3 features for enhancement:
  // 1. Use TC3 Temperature Controller to implement more advanced control algorithms
  // 2. Implement data logging using TwinCAT Scope View for temperature trend analysis
  // 3. Consider using TwinCAT HMI for creating a user interface to monitor and control the temperature<|endoftext|>
  