Applied Computer Systems

How Do I Calibrate the LINK System Touch Screen (ELO)

Download PDF:  KB0410

I am unable to select the functions on my LINK System touch screen that I want to select.  When selecting one button, a button that is beside it is selected.

The LINK System’s touch screen may occasionally require a calibration.  Calibrating the touch screen will synchronize the cursor to the point at which your finger touches the screen.


IMPORTANT: You will be accessing sensitive areas of the touchscreen’s configuration and therefore must be very careful to follow these directions precisely or risk leaving your unit in a non-functioning state.

IMPORTANT: It is advisable to read all of the following directions before beginning.

  1. Plug in a USB keyboard to the touchscreen. The USB ports can be found underneath the front part of the unit. You may need to remove the long plastic covering before the ports are accessible.
  2. Return to the default screen for LinkSystem control. You should see three rows of buttons above the student icons.
  3. Press the green button labeled Settings near the top-left corner of the screen.
  4. Press the blue button labeled Shutdown in the top-right corner of the screen. TIMING: You must perform the next step quickly enough to prevent the default operation (shutdown) from activating. If you miss the timing, you must reboot your touchscreen and begin again from step #2.
  5. Press the d (delay) button on the keyboard. You should see a message indicating that the system has been placed into a waiting (delayed) state.
  6. Hold in the Alt button and press F2. The screen will then prompt you for a login.
  7. The login is as follows. Enter the login and password pressing ENTER after each line.
    login: root
                Password: acs
  8. If you have correctly entered the login information, you will now be given a shell prompt. The prompt ends with <~> which tells you that the shell is ready for another command.IMPORANT: When entering commands at the shell prompt bear in mind that capitalization matters. You must enter each character exactly as the directions indicate.
  9. Hold in the Alt button and press F3. Login once more to get another shell prompt. We will use this prompt at a later stage. Hold in the Alt button and press F2 to return to the first prompt.
  10. Enter the command rwroot and press ENTER. The command will execute and you will be returned to the shell prompt.
  11. Enter the command vi /etc/X11/xorg.conf and press ENTER. You should now see the contents of the configuration file which holds the touchscreen calibration settings.
  12. Press the Page Down button on the keyboard until you see the line reading Identifier “TouchScreen”.
  13. Press i (as in “india”) on the keyboard to begin editing the file.
  14. Finding the perfect calibration values is a trial-and-error process. If your touchscreen’s calibration is off in the horizontal direction you will want to tweak the MinX and MaxX settings. Similarly, if it is off in the vertical direction you will want to tweak the MinY and MaxY settings. Adjust them in increments of 50 or 100 to start with.
  15. Press ESC (escape) on the keyboard to leave the editing mode.
  16. Press :w (colon, w) followed by ENTER to save your changes.
  17. Hold in the Alt button and press F3 to switch to the second shell prompt that we created above.
  18. Type xinit and press ENTER to start the controller software. At the point you will be able to test the calibration settings that you entered. Make a note as to what needs to change (horizontal and/or vertical calibration), then press Settings followed by Shutdown to return to the prompt.
  19. Hold in the Alt button and press F2 to switch back to the editor.
  20. Proceed with these instructions only if the calibration is now to your satisfaction. If you need to continue adjusting the calibration, return to step #13 now.
  21. Press :q (colon, q as in “quit”) followed by ENTER to return to the shell prompt.
  22. Enter the command roroot and press ENTER. The command will execute and you will be returned to the shell prompt.
  23. Hold in the Alt button and press F1 to switch back to the shutdown menu.
  24. Press r (as in “reboot”) to reboot the system.
  25. Verify that the controller software starts as usual and that the calibration is correct. At this point you may again use the touchscreen to control your LinkSystem.If at any point you lose your place or the directions do not seem to apply to the screen you are seeing, first try going immediately to step #22, finish the directions through #24, and then either return to the beginning of the directions as if you are starting from scratch or contact ACS for assistance.

If calibrating the touch screen does not appear to fix your problem, call Applied Computer Systems, Inc. at 800-237-5465 for technical support.