Velocity-Based Straight-Line Move C/C++ Code

The following example code is not necessarily complete, and may not compile if copied exactly. Refer to the examples folder on the NI-Motion CD for files that are complete and compile as is.

// Main function
void main(void)
{

   u8   boardID;           // Board identification number
   u8   axis;              // Axis number
   u16 csr   = 0;          // Communication status register
   u16 axisStatus;         // Axis status
   i32 moveTime1;          // Time for the 1st segment
   i32 moveTime2;          // Time for the 2nd segment
   i32 initialTime;
   i32 currentTime;

   // Variables for modal error handling
   u16 commandID;          // The commandID of the function
   u16 resourceID;         // The resource ID
   i32 errorCode;          // Error code


   ///////////////////////////////
   // Set the board ID
   boardID = 3;
   // Set the axis number
   axis = 1;
   // Move time for the first segment
   moveTime1 = 5000; //milliseconds
   // Move time for the second segment
   moveTime2 = 10000; //milliseconds
   ////////////////////////////////

   //------------------------------------------------------------
   // First segment
   //------------------------------------------------------------
   // Set the velocity for the move (in counts/sec)
   err = flex_load_velocity(boardID, axis, 10000, 0xFF);
   CheckError;

   // Set the acceleration for the move (in counts/sec^2)
   err = flex_load_acceleration(boardID, axis, NIMC_ACCELERATION, 100000, 0xFF);
   CheckError;

   // Set the deceleration for the move (in counts/sec^2)
   err = flex_load_acceleration(boardID, axis, NIMC_DECELERATION, 100000, 0xFF);
   CheckError;

   // Set the jerk (s-curve value) for the move (in sample periods)
   err = flex_load_scurve_time(boardID, axis, 100, 0xFF);
   CheckError;

   // Set the operation mode to velocity
   err = flex_set_op_mode(boardID, axis, NIMC_VELOCITY);
   CheckError;

   // Start the move
   err =  flex_start(boardID, axis, 0);
   CheckError;

   // Wait for the time for first segment
   initialTime = timeGetTime();
   do
   {
      // Check the move complete status/following error/axis off status
      err = flex_read_axis_status_rtn(boardID, axis, &axisStatus);
      CheckError;

      // Read the communication status register and check the modal errors
      err = flex_read_csr_rtn(boardID, &csr);
      CheckError;

      // Check the modal errors
      if (csr & NIMC_MODAL_ERROR_MSG)
      {
         err = csr & NIMC_MODAL_ERROR_MSG;
         CheckError;
      }

      // Get the current time and check if time is over for the first segment
      currentTime = timeGetTime();
      if((currentTime - initialTime) >=  moveTime1) break;

      Sleep (50); // Check every 50 ms

   }while (!(axisStatus & NIMC_MOVE_COMPLETE_BIT) && !(axisStatus & NIMC_FOLLOWING_ERROR_BIT) && !(axisStatus & NIMC_AXIS_OFF_BIT)); // Exit on move complete/following error/axis off

   //------------------------------------------------------------
   // Second segment
   //------------------------------------------------------------
   // Set the velocity for the move (in counts/sec)
   err = flex_load_velocity(boardID, axis, 6568, 0xFF);
   CheckError;

   // Start the move - to update the velocity
   err =  flex_start(boardID, axis, 0);
   CheckError;

   // Wait for the time for second segment
   initialTime = timeGetTime();
   do
   {
      // Check the move complete status/following error/axis off status
      err = flex_read_axis_status_rtn(boardID, axis, &axisStatus);
      CheckError;

      // Read the communication status register and check the modal errors
      err = flex_read_csr_rtn(boardID, &csr);
      CheckError;

      // Check the modal errors
      if (csr & NIMC_MODAL_ERROR_MSG)
      {
         err = csr & NIMC_MODAL_ERROR_MSG;
         CheckError;
      }

      // Get the current time and check if time is over for the second segment
      currentTime = timeGetTime();
      if((currentTime - initialTime) >=  moveTime2) break;

      Sleep (50); // Check every 50 ms

   }while (!(axisStatus & NIMC_MOVE_COMPLETE_BIT) && !(axisStatus & NIMC_FOLLOWING_ERROR_BIT) && !(axisStatus & NIMC_AXIS_OFF_BIT)); // Exit on move complete/following error/axis off


   // Decelerate the axis to a stop
   err = flex_stop_motion(boardID, axis, NIMC_DECEL_STOP, 0);
   CheckError;

   return;      // Exit the Application


   /////////////////////////////////////////////////////////////////////////
   // Error Handling
   //
   nimcHandleError; //NIMCCATCHTHIS:
   
   // Check to see if there were any Modal Errors
   if (csr & NIMC_MODAL_ERROR_MSG){
      do{
         // Get the command ID, resource and the error code of the modal
         // error from the error stack on the board
         flex_read_error_msg_rtn(boardID,&commandID,&resourceID,&errorCode);
         nimcDisplayError(errorCode,commandID,resourceID);

         // Read the Communication Status Register
         flex_read_csr_rtn(boardID,&csr);

      }while(csr & NIMC_MODAL_ERROR_MSG);
   }
   else       // Display regular error
      nimcDisplayError(err,0,0);
   return;    // Exit the Application
}