Operating a Variable Delay Line

VDL controls on the Hardware Control Tool GUI are located on the Miscellaneous tab. The GO HOME button homes the VDL and adjustment of the numeric VDL Position (mm) control field immediately commands the VDL to move to the requested absolute position.

Before operating the VDL, please read the general instructions on using the AxsunOCTControl_LW API in your custom application.

See the AxsunOCTControl_LW function reference for details on calling the functions discussed here.

Homing the VDL

The VDL Homing operation must be performed for each power-on cycle of the Laser Engine board by calling axHomeVDL(). The carriage is moved in the negative direction until it reaches the home limit switch and then backs off the switch slightly. All subsequent motion within the delay range is referenced to this 0.00 mm position. This function returns after requesting the homing operation from the VDL controller; it does not wait for the mechanical homing operation to complete before returning.

Moving the VDL to a Desired Position

The VDL can be moved in a relative fashion (positive or negative displacement from the current position) with axMoveRelVDL(..) or in an absolute fashion (directly to a fixed position within the delay range) with axMoveAbsVDL(..). Any requests to move the VDL to a position which is outside of its allowable delay range (0 to 15 mm) will be ignored. These functions return immediately after requesting the the move operation from the VDL controller; they do not wait for the requested move operation to complete before returning.

Querying the Status of the VDL

The status of the VDL hardware can be queried or polled with axGetVDLStatus(..), providing information useful especially during a home or move operation, such as: instantaneous position and speed, target position for the current move, and limit switch state. After issuing a home or move command, poll this function to determine if the operation has completed or failed with an error.

Stopping the VDL

A VDL operation in progress can be stopped immediately using axStopVDL(). This function returns after requesting the stop operation from the VDL controller; it does not wait for the mechanical operation to stop before returning.

Before operating the VDL, please read the general instructions on using the AxsunOCTControl API in your custom application.

Homing the VDL

The VDL Homing operation must be performed for each power-on cycle of the Laser driver board. The carriage is moved in the negative direction until it reaches the home limit switch and then backs off the switch slightly. All subsequent motion within the delay range is referenced to this 0.00 mm position. This method returns after requesting the homing operation from the VDL controller; it does not wait for the mechanical homing operation to complete before returning.

uint  HomeVDL()       // returns 0 (success) or error code

Moving the VDL to a Desired Position

The VDL can be moved in a relative fashion (positive or negative displacement from the current position) or absolute fashion (directly to a fixed position within the delay range). Any requests to move the VDL to a position which is outside of its allowable delay range (0 to 15 mm) will be ignored. These methods return immediately after requesting the the move operation from the VDL controller; they do not wait for the requested move operation to complete before returning.

uint  MoveRelVDL(    // returns 0 (success) or error code
    float Position,  // distance to move relative to the current position (mm)
    float Speed)     // the speed at which to move (mm/sec)

uint  MoveAbsVDL(    // returns 0 (success) or error code
    float Position,  // the desired position (mm) in absolute terms 
    float Speed)     // the speed at which to move (mm/sec)

Querying the Status of the VDL

The status of the VDL hardware can be queried or polled, providing information useful especially during a home or move operation, such as: instantaneous position and speed, target position for the current move, and limit switch state. After issuing a home or move command, poll this method to determine if the operation has completed or failed with an error.

uint  GetStepperStatus(           // returns 0 (success) or error code
    ref float Position,           // current position (mm)
    ref float Target,             // target position (mm) during a move operation
    ref float Speed,              // current speed (mm/sec) during a move operation
    ref uint State,               // 1 = idle, 
                                  // 2 = moving, 
                                  // 3 = seeking home, 
                                  // 4 = backing off home, 
                                  // 5 = at home,
                                  // 10 = error state
    ref bool HomeSwitch,          // indicates if the home switch is tripped
    ref bool LimitSwitch,         // indicates if limit switch is tripped (far end of travel)
    ref int ErrorFromLastHome,    // error accumulated since last Home operation (in motor microsteps)
    ref uint LastMoveTime,        // time (sec) taken by the last issued move command
    ref uint Error)               // firmware error code (0 if no error)

Stopping the VDL

A VDL operation in progress can be stopped immediately using StopVDL(). This method returns after requesting the stop operation from the VDL controller; it does not wait for the mechanical operation to stop before returning.

uint  StopVDL()       // returns 0 (success) or error code