الغلايات والتحكم الآلي في الغلايات - الدليل الشامل

// Ladder Logic for Water Level Control
// Siemens S7-1200 Example

// Three-element control: Feedwater flow, Steam flow, Drum level
ORGANIZATION_BLOCK "WaterLevelControl"
VAR
  DrumLevel : REAL; // Current drum level (%)
  Setpoint : REAL := 50.0; // Desired level (%)
  Error : REAL; // Control error
  FeedwaterValve : REAL; // Feedwater valve position (0-100%)
  PID_Instance : PID_Compact; // PID controller instance
END_VAR

// Read drum level from sensor
DrumLevel := "LevelTransmitter".PV;

// Calculate error
Error := Setpoint - DrumLevel;

// Execute PID control
PID_Instance.Setpoint := Setpoint;
PID_Instance.Input := DrumLevel;
PID_Instance.CyclicExecute();
FeedwaterValve := PID_Instance.Output;

// Output to feedwater control valve
"FeedwaterValve".Setpoint := FeedwaterValve;