Block scan for mid-program startup

Application

The Block scan function allows you to start an NC program at any desired NC block. The control factors workpiece machining up to this NC block into the calculations. For example, the control will switch on the spindle before the start.

Requirement

  • The function must be enabled by your machine manufacturer.
  • The Block scan function must be enabled and configured by your machine manufacturer.

Description of function

 
Tip

The following information also applies to pallet tables and job lists.

If the NC program was interrupted under the following conditions, the control saves the interruption point:

  • The Internal stop button
  • Emergency stop
  • Power failure

If, while restarting, the control finds a saved point of interruption, then it outputs a message. You can then execute a block scan directly to the point of interruption. The control displays the message when you switch to Program Run operating mode for the first time.

You have the following options for a block scan:

At the start of the block scan, the control resets the data, as with a selection of a new NC program. During the block scan you can activate or deactivate Single Block mode.

The Block scan window

The Block scan window with saved interruption point and open Advanced area

The Block scan window provides the following data:

Row

Meaning

Row number

Row number in the pallet table

Row number in the pallet table at the time of interruption

Program

Path of the active NC program

Path of the NC program that is active at the time of interruption

Block number

Number of the NC block at which program run should start

The control proposes the currently selected NC block. You can open the Search column from the Block scan window.

Number of the NC block that was active at the time of interruption

Repetitions

Number of the repetition for mid-program startup if the desired NC block is located within a program-section repeat or a program loop.

Number of the repetition at the time of interruption if the interruption was located within a program-section repeat or program loop.

Point table

Path of the point table

Selection by means of a selection window

Path of the active point table at the time of interruption

Point number

Row in the point table

Active row in the point table at the time of interruption

Select the interruption point by using the Select last button in the Advanced area.

Performing a single-level block scan

To start in an NC program by using a single-level block scan:

    1. Select the Program Run operating mode

    1. Select Block scan
    2. The control opens the Block scan window. The fields Program, Block number and Repetitions contain the current values.

    1. Enter the Program as needed
    2. Enter the Block number
    3. Enter the Repetitions as needed

    1. If applicable, open the Extended area

    1. If required, use Select last to start at a saved interruption point

    1. Press the NC Start key
    2. The control starts the block scan and calculates up to the entered NC block.
    3. If you have changed the machine status, the control displays the Restore machine status window.

    1. Press the NC Start key
    2. The control restores the machine status (e.g., TOOL CALL or M functions).
    3. If you have changed the axis positions, the control displays the Axis sequence for return to contour: window.

    1. Press the NC Start key
    2. Using the displayed positioning logic, the control moves to the required positions.
    3.  
      Tip

      You can also position the axes individually in a self-selected sequence.

      Positioning the axes in a self-selected sequence

    1. Press the NC Start key
    2. The control resumes execution of the NC program.

    Performing a multi-level block scan

    If you, for example, start in a subprogram that is called several times by the main program, then use the multi-level block scan. For this, you first go to the desired subprogram call and then continue the block scan. The same procedure is used for called NC programs.

    To start in an NC program by using a multi-level block scan:

      1. Select the Program Run operating mode

      1. Select Block scan
      2. The control opens the Block scan window. The fields Program, Block number and Repetitions contain the current values.

      1. Perform a block scan to the first start-up point:
      2. Performing a single-level block scan

      1. Activate the Single Block toggle switch as needed

      1. Press the NC Start key to execute individual NC blocks as needed

      1. Select Continue block scan

      1. Define the NC block for mid-program startup

      1. Press the NC Start key
      2. The control starts the block scan and calculates up to the entered NC block.
      3. If you have changed the machine status, the control displays the Restore machine status window.

      1. Press the NC Start key
      2. The control restores the machine status (e.g., TOOL CALL or M functions).
      3. If you have changed the axis positions, the control displays the Axis sequence for return to contour: window.

      1. Press the NC Start key
      2. Using the displayed positioning logic, the control moves to the required positions.
      3.  
        Tip

        You can also position the axes individually in a self-selected sequence.

        Positioning the axes in a self-selected sequence

      1. Select Continue block scan again as needed
      2. Repeat the steps

      1. Press the NC Start key
      2. The control resumes execution of the NC program.

      Block scan in point tables

      To start in a point table:

        1. Select the Program Run operating mode

        1. Select Block scan
        2. The control opens the Block scan window. The fields Program, Block number and Repetitions contain the current values.

        1. Open the Extended area

        1. Under Point table, select the point table

        1. Point number: Select the row number of the point table for mid-program startup

        1. Press the NC Start key
        2. The control starts the block scan and calculates up to the entered NC block.
        3. If you have changed the machine status, the control displays the Restore machine status window.

        1. Press the NC Start key
        2. The control restores the machine status (e.g., TOOL CALL or M functions).
        3. If you have changed the axis positions, the control displays the Axis sequence for return to contour: window.

        1. Press the NC Start key
        2. Using the displayed positioning logic, the control moves to the required positions.
        3.  
          Tip

          You can also position the axes individually in a self-selected sequence.

          Positioning the axes in a self-selected sequence

         
        Tip

        If you would like to use the block scan function to start in a point pattern, then use the same procedure. Define the desired point for mid-program startup in the Point number field. The first point in the point pattern has the number 0.

        Pattern definition cycles

        Block scan in pallet tables

        To start in a pallet table:

          1. Select the Program Run operating mode

          1. Select Block scan
          2. The control opens the Block scan window.

          1. Row number: Enter the row number of the pallet table

          1. Enter the Program as needed
          2. Enter the Block number
          3. Enter the Repetitions as needed

          1. If applicable, open the Extended area

          1. If required, use Select last to start at a saved interruption point

          1. Press the NC Start key
          2. The control starts the block scan and calculates up to the entered NC block.
          3. If you have changed the machine status, the control displays the Restore machine status window.

          1. Press the NC Start key
          2. The control restores the machine status (e.g., TOOL CALL or M functions).
          3. If you have changed the axis positions, the control displays the Axis sequence for return to contour: window.

          1. Press the NC Start key
          2. Using the displayed positioning logic, the control moves to the required positions.
          3.  
            Tip

            You can also position the axes individually in a self-selected sequence.

            Positioning the axes in a self-selected sequence

           
          Tip

          If the program run of a pallet table has been canceled, the control will suggest the most recently selected NC block of the most recently executed NC program as a point of interruption.

          Notes

           
          Notice
          Danger of collision!
          If you select an NC block in program run using the GOTO function and then execute the NC program, the control ignores all previously programmed NC functions (e.g., transformations). This means that there is a risk of collision during subsequent traversing movements!
          1. Use GOTO only when programming and testing NC programs
          2. Only use Block scan when executing NC programs
           
          Notice
          Caution: Danger to the tool and workpiece!
          If program run is interrupted within a called NC program, the control always offers the first call of this NC program as a point of interruption for mid-program startup. If program run was interrupted in a later call, the control might then execute parts of the program that have already run.
          1. Use multi-stage mid-program startup to manually navigate to the point of interruption
           
          Notice
          Danger of collision!
          The Block scan function skips over the programmed touch probe cycles. As a result, the result parameters contain no values or, possibly, incorrect values. If the subsequent machining operation uses these result parameters, then there is a risk of collision!
          1. Use the Block scan function in multiple steps
          • The TNC7 basic can move up to four axes simultaneously. If an NC block commands movement of more than four axes, the control displays an error message. When the control reads such a NC block during the Block scan, it will also display an error message.
          • The control only displays the dialogs required by the process in the pop-up window.
          • Use the +, -, *, /, (, and ) keys for calculations in the numerical input fields.
          • If you use the block scan to start in a pallet table, the control will always execute the chosen row in the pallet table as a workpiece-oriented process. After the pallet table line selected in the Block scan, the control resumes machining according to the defined machining method.
          • Tool-oriented machining

          • Even after an internal stop, the control shows the number of repetitions on the LBL tab of the Status workspace.
          • The LBL tab

          • The Block scan function must not be used in conjunction with the following functions:
            • Touch probe cycles 0, 1, 3, and 4 during the block scan search phase
          • HEIDENHAIN recommends switching the spindle on with M3 or M4 after every tool call. That way you avoid problems during program run, such as when restarting after an interruption.