Device Description
Touch-Panels for Industrial Automation
DVI-Panel
Notes on the touch-screen
© 2005 by Moeller GmbH
02/05 AWB2720-1524GB
33
8 Notes on the touch-screen
8.1 B
ASIC TOUCH
-
SCREEN FUNCTION
Devices with infrared
touch-screen
The touch-screen operates on the active light matrix principle in the infra-
red range. Interrupting this light matrix at any point will initiate an operation
if a touch activated screen element was touched (e.g. a button).
A timeout is initiated if the light matrix is interrupted for longer than
approx.
7s
(this timeout can be configured up to max. 15s within the touch-driver)
.
The touch panel then switches to the “non-actuated” state, and further
operations cannot be initiated until the initial touch actuation has stopped
(e.g. button released) or the touch is actuated again. Several simultaneous
touch actuations at different points cannot be evaluated.
Devices with resistive
touch-screen
The resistive touch-screen operates on an analog principle. Pressing the
touch-screen at any point results in an electrical resistance which is
measured and will be calculated into a position by the touch controller. This
initiates an operation if a touch activated screen element was touched (e.g.
a button).
Because of this function principle the resistive touch-screen has to be
calibrated. The first calibration is already done when delivered. A
recalibration of the touch-screen is necessary when the touch position is
different to the screen, e.g. because of ageing, temperature, etc. The
calibration can be activated within an EPAM project (see EPAM manual,
Button-Action „Touch_calibrate”). Details see XVC/XCC manual and EPAM-
manual.
8.2 P
OWER UP FUNCTION TEST
If Power up function tests are performed or not depends on the touch-type
(infrared or resistiv) and the used PC system (XCC or Standard-PC) and the
installed software.
Devices with infrared touch-screen
A power up function test will be performed in combination with XCC-devices
with EPAM-Visualization-Software. (Details see XVC/XCC manual and
EPAM-manual)
Devices with resistive touch-screen
Because of function principle it is not possible to do a function test on
devices with resistive touch-screen.
