Setting up Two Touch Screens for Stretched Desktop
This application note explains how to calibrate two NextWindow touch
screens to work with a stretched desktop - where the desktop spans across
two display screens, with the left hand-end of the task bar in the left hand
screen and the right-hand of the task bar in the right-hand screen.
(Note: The other common multiple-screen configuration is the
Extended Desktop.)
Stretching the desktop across two monitors is a function of the Windows
operating system and the graphics card, and is not covered here.
To set up the two touch screens requires NextWindow's software, USB Config.
Calibration Procedure
The two touch screens are calibrated separately (i.e., only one touch
screen should be connected to the computer at a time).
We will call the two touch screens "Touch Panel 1" and "Touch Panel 2" respectively.
| 1. |
Connect Touch Panel 1 to the computer using the USB cable. |
| 2. |
Run USB Config and wait a few seconds for it to establish communications (touch
panel configuration data appears on the USB Config tabs). |
| 3. |
Choose File / Save to save the current Touch Panel 1 settings to a file on
the computer for backup purposes. |
| 4. |
Press SHIFT CTRL C simultaneously to access the Custom Calibration Points dialog
(see screen shot below). |
| 5.
|
Enter the calibration points for Touch Panel 1 (See
X and Y Calibration
Values below). |
| 6.
|
Click the [Apply] button to commit these settings. |
| 7. |
Click the [Save] button to save the settings onto Touch Panel 1 firmware. |
| 8. |
Unplug Touch Panel 1 and plug in Touch Panel 2. |
| 9. |
Wait a few seconds for USB Config to establish communications with
Touch Panel 2. |
| 10. |
Choose File / Save to save the current Touch Panel 2 settings to a file on
the computer for backup purposes. |
| 11. |
Enter the calibration points for Touch Panel 2 (See
X and Y Calibration
Values below). |
| 12. |
Click the [Apply] button to commit these settings. |
| 13. |
Click the [Save] button to save the settings onto Touch Panel 2 firmware. |
| 14. |
Close USB Config. |
| 15. |
Plug in Touch Panel 1 to a different USB port from Touch Panel 2. |
This completes the calibration procedure. The two touch panels now behave as
one touch screen covering both display units.
USB Config Dialog
The [Left Half of Screen] button automatically sets the calibration
points to values within the left half of the screen.
Returning to Default Settings
To return to default
values, go to the General tab of
USB Config, and drag the calibration offset
slider to zero and then back to 13%. Then click [Save] to save the settings
to the touch screen controller board.
A touch panel has an XY range of 32767 by 32767. In order to calibrate
correctly, we need to split
the X range across the two touch panels. So the X-range for Screen 1 will be 0 to 16383 and the X-range for
screen 2 will be 16384 to 32767.
The diagram below shows the X and Y calibration points for each touch panel.
Panel 1
|
|
Panel 2
|
|
Top left |
2000, 4000 |
Top left |
18384, 4000 |
Bottom right |
14383, 28767 |
Bottom right |
30767, 28767 |
|
