Touch Switches - Omron NT20S-ST121B-EV3 User Manual

Touch Switches

4-7

Touch Switches

!Caution Do not use input functions such as PT touch switches for applications where
!Caution Press touch switches with a force of no greater than 30 N.
!Caution Do not press touch switches carelessly while the backlight is off or while noth-
!Caution If touch switches are pressed in rapid succession, their inputs may not be suc-
Note
152
The NT20 has a function whereby input operations can be performed by using
touch panels displayed on the screen. NT20 screens can be switched, or bit
information sent to the Host, by pressing (lightly touching) the "touch
switches" in a panel.
The touch switches can also be made to light up (or flash) and go off like
lamps.
Touch switches are set when creating the screen data with the Support Tool.
This section describes the touch switches that can be displayed, and explains
the screen switching function and the system key function.
For details on how the status of the currently displayed touch switch is sent to
the Host, refer to 5-3-4 Lit (Flashing) and Unlit Touch Switch Status (Changing
the Status of Allocated Bits) on page 195, Lamp and Touch Switch Display
(Bit Specification) on page 223, and Lamp and Touch Switch Display (Number
Specification) on page 223.
For details on how the status of touch switches is ascertained by the Host,
refer to 5-3-5 Notifying the Host That a Switch Has Been Pressed (Determin-
ing Touch Switch Status) on page 196, and Lamp and Touch Switch Display
Status Enquiry on page 224.
danger to human life or serious property damage is possible or for emergency
switch applications.
ing is displayed on the screen. Otherwise the system may operate unpredict-
ably.
Only press touch switches after confirming system safety.
cessfully received.
Confirm that the input of a touch switch has been successfully received before
moving on to the next operation.
Caution on pressing touch switches at 3 points
When multiple touch switches are created at the relative positions indicated in
the example below, malfunctions may occur due to the characteristics of this
switch configuration.
Example 1: When switches are created at positions A and B and at the points
where the vertical and horizontal lines extending from these two points inter-
sect, i.e. points C and D:
A
C
B
D
Smallest touch switch frame
• When switches A, B, and C are switched on at
the same time, switch D is also assumed to
have been switched on due to the configuration
of the touch switches.
• When switches A, B, and D are switched on at the
same time, switch C is also assumed to have been
switched on due to the configuration of the touch
switches.
Section 4-7