text: <user>
  Create a function block for temperature control in TwinCAT Structured Text<|endoftext|>
  <assistant>
  FUNCTION_BLOCK FB_TemperatureControl
  VAR_INPUT
      fSetpoint       : LREAL;    // Temperature setpoint in degrees Celsius
      fCurrentTemp    : LREAL;    // Current temperature reading in degrees Celsius
      bEnable         : BOOL;     // Enable control
  END_VAR
  
  VAR_OUTPUT
      fHeaterOutput   : LREAL;    // Heater output (0-100%)
      bError          : BOOL;     // Error flag
      nErrorID        : UDINT;    // Error ID
  END_VAR
  
  VAR
      fbPID           : FB_CTRL_PID;    // PID controller function block
      fKp             : LREAL := 1.0;   // Proportional gain
      fTn             : LREAL := 10.0;  // Integral time constant
      fTv             : LREAL := 1.0;   // Derivative time constant
  END_VAR
  
  // Main control logic
  IF bEnable THEN
      // Configure and run PID controller
      fbPID(
          fSetpointValue    := fSetpoint,
          fActualValue      := fCurrentTemp,
          fKp               := fKp,
          fTn               := fTn,
          fTv               := fTv,
          fCtrlCycleTime    := T#100MS,
          fManSyncValue     := 0,
          bSync             := FALSE,
          eMode             := E_CTRL_MODE.eCTRL_MODE_ACTIVE
      );
      
      // Set heater output based on PID result
      fHeaterOutput := LIMIT(0, fbPID.fCtrlOutput, 100);
  ELSE
      // Disable heater when control is not enabled
      fHeaterOutput := 0;
      fbPID(bSync := TRUE, fManSyncValue := 0, eMode := E_CTRL_MODE.eCTRL_MODE_INACTIVE);
  END_IF
  
  // Error handling
  IF fbPID.bError THEN
      bError   := TRUE;
      nErrorID := fbPID.nErrorId;
  ELSE
      bError   := FALSE;
      nErrorID := 0;
  END_IF
  
  (* 
  This function block implements a temperature control system using a PID controller.
  It takes a setpoint and current temperature as inputs, and outputs a heater control signal.
  The PID parameters (Kp, Tn, Tv) can be tuned for optimal performance.
  *)
  
  // Suggested TwinCAT 3 features or programming techniques:
  // 1. Use Scope View to visualize and tune PID controller performance.
  // 2. Implement a state machine for more complex temperature control scenarios.
  // 3. Consider using TwinCAT's Temperature Controller Library for advanced features.<|endoftext|>
  