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
      fActualTemp     : 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
      fbPID           : FB_CTRL_PID;    // PID controller function block
      fError          : REAL;           // Temperature error
      fIntegralTerm   : REAL;           // Integral term for PID
      tTaskCycleTime  : TIME := T#10MS; // Task cycle time
  END_VAR
  
  // Main program
  IF bEnable THEN
      // Calculate error
      fError := fSetpoint - fActualTemp;
      
      // Configure and execute PID controller
      fbPID(
          fSetpointValue    := fSetpoint,
          fActualValue      := fActualTemp,
          fKp               := 2.0,
          fTn               := T#5S,
          fTv               := T#1S,
          fTd               := T#500MS,
          tTaskCycleTime    := tTaskCycleTime,
          fManSyncValue     := 0,
          bSync             := FALSE,
          eMode             := E_CTRL_MODE.eCTRL_MODE_ACTIVE,
          bHold             := FALSE
      );
      
      // Set heater output
      fHeaterOutput := LIMIT(0, fbPID.fOut, 100);
      
      // Check for alarm condition (example: temperature too high)
      bAlarm := fActualTemp > (fSetpoint + 10);
  ELSE
      // Disable heater when not enabled
      fHeaterOutput := 0;
      bAlarm := FALSE;
  END_IF
  
  (* 
  Temperature Control Concept:
  This function block implements a PID-based temperature control system.
  It takes a setpoint and actual temperature as inputs, calculates the
  error, and uses a PID controller to determine the appropriate heater
  output to maintain the desired temperature.
  
  Related TwinCAT 3 features/techniques to enhance this implementation:
  1. TC3 Temperature Controller: A specialized library for temperature control applications.
  2. TC3 Scope View: For real-time monitoring and tuning of the PID controller.
  3. Structured error handling using TC3 PLC Library.
  *)<|endoftext|>
  