text: <user>
  Create a function block for a high-precision servo drive control in TwinCAT Structured Text, incorporating features for 100kHz update rate, sub-nanometer precision, and real-time data logging.<|endoftext|>
  <assistant>
  FUNCTION_BLOCK FB_HighPrecisionServoDrive
  VAR_INPUT
      bEnable         : BOOL;          // Enable servo drive
      fTargetPosition : LREAL;         // Target position in nanometers
      fVelocity       : LREAL;         // Velocity in nm/s
      fAcceleration   : LREAL;         // Acceleration in nm/s^2
  END_VAR
  
  VAR_OUTPUT
      bError          : BOOL;          // Error flag
      nErrorID        : UDINT;         // Error ID
      fActualPosition : LREAL;         // Actual position in nanometers
      fActualVelocity : LREAL;         // Actual velocity in nm/s
      bInPosition     : BOOL;          // In-position flag
  END_VAR
  
  VAR
      fbAxis          : AXIS_REF;      // Axis reference
      fbPower         : MC_Power;      // Power function block
      fbMoveAbsolute  : MC_MoveAbsolute; // Move absolute function block
      fbReadActualPosition : MC_ReadActualPosition; // Read actual position
      fbReadActualVelocity : MC_ReadActualVelocity; // Read actual velocity
      
      // High-resolution timer for 100kHz update rate
      fbTimer         : TON;
      tCycleTime      : TIME := T#10US; // 10 microseconds for 100kHz
      
      // Data logging
      aPositionLog    : ARRAY[0..999] OF LREAL;
      aVelocityLog    : ARRAY[0..999] OF LREAL;
      nLogIndex       : UINT := 0;
  END_VAR
  
  // Main program
  fbTimer(IN := NOT fbTimer.Q, PT := tCycleTime);
  
  IF fbTimer.Q THEN
      // 100kHz update cycle
      
      // Power the servo drive
      fbPower(
          Axis := fbAxis,
          Enable := bEnable,
          Enable_Positive := bEnable,
          Enable_Negative := bEnable,
          Override := 100.0
      );
      
      // Execute absolute move
      fbMoveAbsolute(
          Axis := fbAxis,
          Execute := bEnable,
          Position := fTargetPosition,
          Velocity := fVelocity,
          Acceleration := fAcceleration,
          Deceleration := fAcceleration
      );
      
      // Read actual position and velocity
      fbReadActualPosition(Axis := fbAxis, Enable := TRUE);
      fbReadActualVelocity(Axis := fbAxis, Enable := TRUE);
      
      fActualPosition := fbReadActualPosition.Position;
      fActualVelocity := fbReadActualVelocity.Velocity;
      
      // Check for in-position
      bInPosition := ABS(fActualPosition - fTargetPosition) < 1.0; // 1 nm tolerance
      
      // Data logging
      aPositionLog[nLogIndex] := fActualPosition;
      aVelocityLog[nLogIndex] := fActualVelocity;
      nLogIndex := (nLogIndex + 1) MOD 1000; // Circular buffer
      
      // Error handling
      IF fbPower.Error OR fbMoveAbsolute.Error THEN
          bError := TRUE;
          nErrorID := SEL(fbPower.Error, fbMoveAbsolute.ErrorID, fbPower.ErrorID);
      ELSE
          bError := FALSE;
          nErrorID := 0;
      END_IF
  END_IF
  
  // Implementation explanation:
  // This function block implements a high-precision servo drive control with 100kHz update rate.
  // It uses MC_Power for enabling the drive and MC_MoveAbsolute for position control.
  // Actual position and velocity are read at each cycle and stored in a circular buffer for logging.
  // The implementation aims for sub-nanometer precision by using LREAL data types for positions.
  
  // Suggested TwinCAT 3 features to enhance this implementation:
  // 1. Use TwinCAT 3 XFC (eXtreme Fast Control) for even more precise timing and I/O synchronization.
  // 2. Implement TwinCAT 3 Scope View for real-time visualization of position and velocity data.
  // 3. Utilize TwinCAT 3 Analytics for advanced data analysis and predictive maintenance.<|endoftext|>
  