text: <user>
  Create a function block for temperature control in TwinCAT Structured Text<|endoftext|>
  <assistant>
  FUNCTION_BLOCK FB_TemperatureControl
  VAR_INPUT
      fSetpoint       : LREAL;    // Desired temperature setpoint
      fCurrentTemp    : LREAL;    // Current temperature reading
      bEnable         : BOOL;     // Enable control
  END_VAR
  
  VAR_OUTPUT
      fHeaterOutput   : LREAL;    // Heater output (0-100%)
      bAlarm          : BOOL;     // Temperature alarm
  END_VAR
  
  VAR
      fbPID           : FB_CTRL_PID;    // PID controller function block
      fError          : LREAL;          // Error between setpoint and current temperature
      tCycleTime      : TIME := T#100MS;// PID cycle time
      fKp             : LREAL := 1.5;   // Proportional gain
      fTn             : LREAL := 30.0;  // Integral time
      fTv             : LREAL := 1.0;   // Derivative time
      fYMax           : LREAL := 100.0; // Maximum output
      fYMin           : LREAL := 0.0;   // Minimum output
  END_VAR
  
  // Main control logic
  IF bEnable THEN
      // Calculate error
      fError := fSetpoint - fCurrentTemp;
      
      // Configure and execute PID controller
      fbPID(
          fSetpointValue    := fSetpoint,
          fActualValue      := fCurrentTemp,
          fKp               := fKp,
          fTn               := fTn,
          fTv               := fTv,
          fTd               := tCycleTime,
          fOutMaxLimit      := fYMax,
          fOutMinLimit      := fYMin,
          bARWactive        := TRUE,
          eMode             := E_CTRL_MODE.eCTRL_MODE_ACTIVE,
          fOut              => fHeaterOutput
      );
      
      // Check for temperature alarm (if temperature is 10% above setpoint)
      bAlarm := fCurrentTemp > (fSetpoint * 1.1);
  ELSE
      // Reset outputs when disabled
      fHeaterOutput := 0.0;
      bAlarm := FALSE;
  END_IF
  
  (* 
  Temperature Control Concept:
  This function block implements a PID-based temperature control system.
  It takes a setpoint and current temperature as inputs, calculates the
  error, and uses a PID controller to determine the appropriate heater
  output. An alarm is triggered if the temperature exceeds 110% of the setpoint.
  *)
  
  // Suggested TwinCAT 3 features and techniques for enhancement:
  // 1. Implement TC_CPUUSAGE function to monitor CPU usage and optimize control loop execution.
  // 2. Use ADSLOGSTR for advanced logging and diagnostics of the temperature control process.
  // 3. Consider implementing a state machine using enumeration for more complex control scenarios.<|endoftext|>
  