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;     // Temperature error
      fIntegral       : REAL;     // Integral term
      fKp             : REAL := 2.0;  // Proportional gain
      fKi             : REAL := 0.1;  // Integral gain
      fMaxOutput      : REAL := 100.0;  // Maximum output
      fMinOutput      : REAL := 0.0;    // Minimum output
      tTaskCycle      : TIME := T#10MS;  // PLC task cycle time
      fHighAlarmLimit : REAL := 90.0;  // High temperature alarm limit
  END_VAR
  
  // Main control logic
  IF bEnable THEN
      // Calculate error
      fError := fSetpoint - fCurrentTemp;
      
      // Update integral term
      fIntegral := fIntegral + fError * (TIME_TO_REAL(tTaskCycle) / 1000.0);
      
      // Calculate PID output
      fHeaterOutput := (fKp * fError) + (fKi * fIntegral);
      
      // Limit output
      fHeaterOutput := LIMIT(fMinOutput, fHeaterOutput, fMaxOutput);
      
      // Check for high temperature alarm
      bAlarm := fCurrentTemp > fHighAlarmLimit;
  ELSE
      // Reset outputs when disabled
      fHeaterOutput := 0.0;
      fIntegral := 0.0;
      bAlarm := FALSE;
  END_IF
  
  (* 
  This function block implements a simple PI (Proportional-Integral) controller
  for temperature regulation. It calculates the heater output based on the 
  difference between the setpoint and current temperature. The integral term
  helps eliminate steady-state error. A high temperature alarm is also included.
  *)
  
  // Suggested TwinCAT 3 features to enhance this implementation:
  // 1. Use TwinCAT 3 Scope View for real-time monitoring and tuning of the control loop.
  // 2. Implement TwinCAT 3 HMI for user-friendly temperature control interface.
  // 3. Utilize TwinCAT 3 Analytics for long-term data logging and performance analysis.<|endoftext|>
  