text: <user>
  Create a function block for a simple temperature control system using TwinCAT 3 Structured Text. The system should read a temperature sensor, compare it to a setpoint, and control a heating element accordingly.<|endoftext|>
  <assistant>
  FUNCTION_BLOCK FB_TemperatureControl
  VAR_INPUT
      fActualTemp     : REAL;    // Current temperature reading
      fSetpoint       : REAL;    // Desired temperature setpoint
      fHysteresis     : REAL;    // Hysteresis to prevent rapid switching
  END_VAR
  
  VAR_OUTPUT
      bHeaterOn       : BOOL;    // Heater control signal
      bAlarm          : BOOL;    // High temperature alarm
  END_VAR
  
  VAR
      fUpperLimit     : REAL;    // Upper temperature limit
      fLowerLimit     : REAL;    // Lower temperature limit
  END_VAR
  
  METHOD FB_init : BOOL
  VAR_INPUT
      bInitRetains    : BOOL; // If TRUE, the retain variables are initialized (warm start / cold start)
      bInCopyCode     : BOOL; // If TRUE, the instance afterwards gets moved into the copy code (online change)
  END_VAR
      fUpperLimit := fSetpoint + fHysteresis / 2;
      fLowerLimit := fSetpoint - fHysteresis / 2;
  END_METHOD
  
  METHOD Control
      // Update control limits
      fUpperLimit := fSetpoint + fHysteresis / 2;
      fLowerLimit := fSetpoint - fHysteresis / 2;
      
      // Control heater based on temperature
      IF fActualTemp < fLowerLimit THEN
          bHeaterOn := TRUE;
      ELSIF fActualTemp > fUpperLimit THEN
          bHeaterOn := FALSE;
      END_IF
      
      // Set alarm if temperature is too high
      bAlarm := (fActualTemp > fSetpoint + 10);
  END_METHOD
  
  Explanation:
  This function block implements a simple temperature control system using a hysteresis control method. It reads the actual temperature, compares it to the setpoint, and controls a heating element to maintain the desired temperature within the specified hysteresis range.
  
  TwinCAT 3 features/techniques to enhance the implementation:
  1. Use TwinCAT 3 Scope View for real-time temperature monitoring and system response analysis.
  2. Implement TwinCAT HMI for user-friendly temperature control interface.
  3. Utilize TwinCAT IoT functions to enable remote monitoring and control of the temperature system.<|endoftext|>
  