Omron NT31 Operation Manuals page 356

Touch Switches
Reference: In the case of (1) in the table above, even a bit whose status is retained by the
Type of
When using host link
notification
When using NT link (DM area)
operation
Momentary (1) Notification in word units
Set (all other bits in the word are
Reset OFF)
(2) Notification in word units
(note that the word contents
are read on display and
Alternate
notification is based on these
contents)
When using touch switch input notification, note the following points.
- In the case of (1) in the table, the other bits in the same word are turned OFF by
notification.
15 14
Bit
0 1
Touch switch notify bit
- In the case of (2) in the table, since notification is executed on the basis of the
contents of the word before the display, the other bits in the word are not over-
written. However, if the contents of the word are changed at the host during
display, they will be rewritten based on the contents before display.
- If the screen is switched while a momentary touch switch is pressed, the touch
switch itself will disappear and the "OFF" status will be notified to the host.
Therefore, in the case of (1) in the table, all the bits in the word will be set to the
"OFF" status.
- When using the host link, since writing in bit units is not possible, the statuses
of bits other than the notify bit in the word allocated to a momentary/set/reset
touch switch are not retained when the screen is switched.
- When using an NT30/NT30C, it is not permissible to allocate a momentary
touch switch and a touch switch allocated another function (alternate, set, or
reset) to the same word, but this is possible with the NT31/NT31C.
- If the status of a bit allocated to an alternate touch switch is changed other than
by touch switch operation — for example by programming console operation
— the correct operation of the alternate touch switch cannot be guaranteed
from that point onward (the ON and OFF states may be transposed).
- In the case of (3) and (4) in the table above, notification has no effect on the
other bits in the word.
KEEP instruction for ladder program self latch operation will be turned OFF. In
order to avoid this, allocate bits other than in the DM area when using the NT link
also.
S Allocation of the notify bit
The notification bit can be allocated to the following host (PC) areas.
Touch switch pressed
1 0
0 1
Section 7-7
When using NT link
(other than DM area)
(3) Notification in bit units
(4) Notification in bit units
15 14
1 0
Bit
0 0
1
Bits other than
notify bit go OFF
0
345