text: <user>
  Create a function block for a simple temperature control system 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
      bHeaterOn       : BOOL;    // Heater control signal
      bError          : BOOL;    // Error flag
      nErrorID        : UDINT;   // Error ID
  END_VAR
  
  VAR
      fHysteresis     : REAL := 1.0;    // Temperature hysteresis
      tOnDelay        : TON;            // On delay timer
      tOffDelay       : TON;            // Off delay timer
      bHeaterState    : BOOL;           // Internal heater state
  END_VAR
  
  METHOD Control
  VAR_INPUT
  END_VAR
  // =========================================================
  
  IF bEnable THEN
      // Check if current temperature is below setpoint minus hysteresis
      IF fCurrentTemp < (fSetpoint - fHysteresis) THEN
          tOnDelay(IN := TRUE, PT := T#5S);
          tOffDelay(IN := FALSE);
          
          IF tOnDelay.Q THEN
              bHeaterState := TRUE;
          END_IF
      // Check if current temperature is above setpoint plus hysteresis
      ELSIF fCurrentTemp > (fSetpoint + fHysteresis) THEN
          tOffDelay(IN := TRUE, PT := T#5S);
          tOnDelay(IN := FALSE);
          
          IF tOffDelay.Q THEN
              bHeaterState := FALSE;
          END_IF
      END_IF
      
      bHeaterOn := bHeaterState;
  ELSE
      bHeaterOn := FALSE;
      bHeaterState := FALSE;
      tOnDelay(IN := FALSE);
      tOffDelay(IN := FALSE);
  END_IF
  
  // Error handling
  IF fCurrentTemp > 100.0 THEN
      bError := TRUE;
      nErrorID := 1; // Overtemperature error
      bHeaterOn := FALSE;
  ELSE
      bError := FALSE;
      nErrorID := 0;
  END_IF
  
  // =========================================================
  END_METHOD
  
  (*
  This function block implements a simple temperature control system with hysteresis.
  It uses timers to prevent rapid cycling of the heater. The control method checks
  if the current temperature is outside the hysteresis range and activates/deactivates
  the heater accordingly. Basic error handling for overtemperature is included.
  *)
  
  // Suggested TwinCAT 3 features or programming techniques to enhance this implementation:
  // 1. Use a PID controller (FB_CTRL_PID) for more precise temperature control.
  // 2. Implement state machine programming for more complex control scenarios.
  // 3. Utilize TwinCAT's Scope View for real-time monitoring and tuning of the control system.<|endoftext|>
  