text: <user>
  Create a function block for a simple temperature control system in TwinCAT Structured Text<|endoftext|>
  <assistant>
  FUNCTION_BLOCK FB_TemperatureControl
  VAR_INPUT
      rSetpoint       : REAL;    // Desired temperature setpoint
      rCurrentTemp    : REAL;    // Current temperature reading
      bEnable         : BOOL;    // Enable control
  END_VAR
  
  VAR_OUTPUT
      rHeaterOutput   : REAL;    // Heater output (0-100%)
      bAlarm          : BOOL;    // High temperature alarm
  END_VAR
  
  VAR
      rError          : REAL;    // Error between setpoint and current temperature
      rKp             : REAL := 2.0;    // Proportional gain
      rMaxTemp        : REAL := 100.0;  // Maximum allowable temperature
  END_VAR
  
  // Main program
  IF bEnable THEN
      // Calculate error
      rError := rSetpoint - rCurrentTemp;
      
      // Simple proportional control
      rHeaterOutput := LIMIT(0.0, rKp * rError, 100.0);
      
      // High temperature alarm
      bAlarm := rCurrentTemp > rMaxTemp;
  ELSE
      rHeaterOutput := 0.0;
      bAlarm := FALSE;
  END_IF
  
  (* 
  This function block implements a simple temperature control system using proportional control.
  It takes a setpoint and current temperature as inputs, and outputs a heater control signal.
  A high temperature alarm is also implemented for safety.
  *)
  
  // Suggested TwinCAT 3 features or programming techniques:
  // 1. Use TwinCAT PLC Library: TE1000 for more advanced PID control
  // 2. Implement data persistence using RETAIN variables for setpoint storage
  // 3. Consider using TwinCAT HMI for creating a user interface for the temperature control system<|endoftext|>
  