text: <user>
  Create a function block for motion control in TwinCAT Structured Text that implements a simple point-to-point movement with error handling and status reporting.<|endoftext|>
  <assistant>
  FUNCTION_BLOCK FB_PointToPointMotion
  VAR_INPUT
      bExecute        : BOOL;     // Command to start the motion
      fTargetPosition : LREAL;    // Target position in user units
      fVelocity       : LREAL;    // Maximum velocity for the movement
  END_VAR
  
  VAR_OUTPUT
      bDone           : BOOL;     // Motion completed successfully
      bBusy           : BOOL;     // Motion is in progress
      bError          : BOOL;     // Error occurred
      nErrorID        : UDINT;    // Error ID if an error occurred
      fActualPosition : LREAL;    // Current actual position
  END_VAR
  
  VAR
      fbMcPower       : MC_Power;
      fbMcMoveAbsolute: MC_MoveAbsolute;
      fbMcReset       : MC_Reset;
      AxisRef         : AXIS_REF;
  END_VAR
  
  // Main program logic
  IF bExecute AND NOT bBusy THEN
      // Enable the axis
      fbMcPower(
          Axis := AxisRef,
          Enable := TRUE,
          EnablePositive := TRUE,
          EnableNegative := TRUE
      );
      
      // Start the point-to-point motion
      fbMcMoveAbsolute(
          Axis := AxisRef,
          Execute := TRUE,
          Position := fTargetPosition,
          Velocity := fVelocity
      );
      
      bBusy := TRUE;
      bDone := FALSE;
      bError := FALSE;
      nErrorID := 0;
  END_IF
  
  // Update status
  bDone := fbMcMoveAbsolute.Done;
  bBusy := fbMcMoveAbsolute.Busy;
  bError := fbMcMoveAbsolute.Error;
  nErrorID := fbMcMoveAbsolute.ErrorID;
  
  // Read actual position
  fActualPosition := AxisRef.NcToPlc.ActPos;
  
  // Error handling
  IF bError THEN
      // Attempt to reset the axis
      fbMcReset(
          Axis := AxisRef,
          Execute := TRUE
      );
  END_IF
  
  // Explanation of the implemented PLC software concept:
  // This function block implements a simple point-to-point motion control using TwinCAT 3 motion control function blocks.
  // It enables the axis, executes an absolute move to the target position, and provides status feedback.
  // Basic error handling is implemented with an automatic reset attempt on error.
  
  // Suggested TwinCAT 3 features or programming techniques to enhance the implementation:
  // 1. Implement a state machine for more complex motion sequences and better control flow.
  // 2. Use structured error handling with custom error codes for more detailed diagnostics.
  // 3. Implement a homing sequence using MC_Home function block for establishing a reference position.<|endoftext|>
  