text: <user>
  Create a function block for motion control in TwinCAT Structured Text<|endoftext|>
  <assistant>
  FUNCTION_BLOCK FB_MotionControl
  VAR_INPUT
      bEnable         : BOOL;    // Enable motion control
      fTargetPosition : LREAL;   // Target position in mm
      fVelocity       : LREAL;   // Target velocity in mm/s
      bHalt           : BOOL;    // Halt motion
      bReset          : BOOL;    // Reset errors
  END_VAR
  
  VAR_OUTPUT
      bDone           : BOOL;    // Motion complete
      bBusy           : BOOL;    // Motion in progress
      bError          : BOOL;    // Error occurred
      nErrorID        : UDINT;   // Error ID
      fActualPosition : LREAL;   // Actual position in mm
      fActualVelocity : LREAL;   // Actual velocity in mm/s
  END_VAR
  
  VAR
      fbAxis          : AXIS_REF;
      fbPower         : MC_Power;
      fbMoveAbsolute  : MC_MoveAbsolute;
      fbHalt          : MC_Halt;
      fbReset         : MC_Reset;
  END_VAR
  
  // Main program logic
  fbPower(
      Axis := fbAxis,
      Enable := bEnable,
      Enable_Positive := bEnable,
      Enable_Negative := bEnable
  );
  
  IF bEnable AND NOT bError THEN
      fbMoveAbsolute(
          Axis := fbAxis,
          Execute := TRUE,
          Position := fTargetPosition,
          Velocity := fVelocity
      );
      
      bBusy := fbMoveAbsolute.Busy;
      bDone := fbMoveAbsolute.Done;
  END_IF
  
  IF bHalt THEN
      fbHalt(
          Axis := fbAxis,
          Execute := TRUE
      );
  END_IF
  
  IF bReset THEN
      fbReset(
          Axis := fbAxis,
          Execute := TRUE
      );
  END_IF
  
  // Update outputs
  fActualPosition := fbAxis.NcToPlc.ActPos;
  fActualVelocity := fbAxis.NcToPlc.ActVelo;
  bError := fbPower.Error OR fbMoveAbsolute.Error OR fbHalt.Error OR fbReset.Error;
  nErrorID := fbPower.ErrorID;
  
  // Error handling
  IF bError THEN
      fbMoveAbsolute(Axis := fbAxis, Execute := FALSE);
      fbHalt(Axis := fbAxis, Execute := FALSE);
  END_IF
  
  This function block implements basic motion control functionality using TwinCAT 3 Structured Text. It includes power control, absolute movement, halt, and reset capabilities. The code adheres to IEC 61131-3 standards and is optimized for the TwinCAT 3 environment.
  
  Related TwinCAT 3 features that could enhance this implementation:
  1. State machines: Implement a state machine to manage different motion states more efficiently.
  2. PLCopen Motion Control function blocks: Utilize additional PLCopen-compliant function blocks for more advanced motion control capabilities.
  3. TwinCAT NC: Integrate with TwinCAT NC for more sophisticated multi-axis coordination and interpolation.<|endoftext|>
  