Omron NB3Q-TW00B Startup Manual Manual page 118

6 Maintenance and Troubleshooting
3
Why is there no response from touch-control
When operating the touch panel, if clicking a component on the screen does not receive a
proper response, the first thing you have to do is to make sure that this button is indeed
operable. If it is confirmed, the problem may result from a touch-control shift. The touch panel is
a panel of 4-wire precision resistors, and because the resistors are subject to impacts from
temperature, humidity and also their own characteristics, it's recommended that touch-control
calibration be carried out yearly.
Calibration method: tweak the DIP switches on the backside of the PT, SW1 to OFF, SW2 to
ON, and restart the PT. A "+" will appear on the screen. Click it, the "+" will shift after the PT
responds. You have to click again and after a total of 5 consecutive clicks, the PT will prompt
you whether the calibration is a success. If it is a success, the PT will skip to the user program
screen, while if it is not a success, the "+" will pop up again, requiring another round of
calibration.
Note After a successful calibration, the DIP switch 2 needs to be set back to OFF, or not, the system will
prompt you for a calibration every time you turn on the power supply.
4
Why is the PT touch-control not responding or being slow to respond
The likely causes are as follows:
(a) The communications are abnormal, and when this happens, the touch-control may not
(b) The touch-control shifts, and change of the operation environment or the touch panel
(c) The touch panel may be damaged or the touch-control circuit may be suffered of a poor
Solutions:
(a) Resolve the communication problem;
(b) Try out a touch-control calibration;
(c) Please contact the supplier printed on the back cover.
5
Why does the PT screen dim or without backlight
The screens we normally see on a PT are displayed in liquid crystal. However, the liquid crystal
itself does not give out light, so it is usually used together with a light source, and so far, the
most commonly used light-emitting equipments for industrial PT products are of CCFL or LED
backlight. The NB-Series touch panel employs LED backlight.
LED backlight: LED, (i.e. Lighting Emitting Diode), is a kind of semiconductor solid light-emitting
device. It uses solid semiconductor chips as the light-emitting material. Surplus energy breaks
out during the process of combination of charge carriers in the semiconductor, triggering
photon emissions, and this is used to display various kinds of information, such as characters,
graphics, images, animations, texts, videos and video signals on display panels. The generally
used LED backlight is made up of an array, e.g. an array of 3×4 with a total of 12 LEDs, and if
one or even more LEDs are not working normally, the screen will dim. When none of the LEDs
is working normally, the screen will have no backlight.
The possible causes for a black screen are as follows:
(a) The power supply to the PT is abnormal;
(b) The PT enters the screen saver (backlight saver) mode;
(c) Control backlight OFF is set through the PLC Control Component;
(d) Backlight broken or the LCD panel is damaged.
Solutions:
(a) Check the power supply to the PT, use a multimeter to measure whether the voltage is
(b) Click the PT screen to exit the screen saver mode;
(c) Check whether control backlight OFF is set through the PLC Control Component in the
(d) Please contact the supplier printed on the back cover.
6-30
respond;
characteristics may cause the touch-control to be unable to respond;
contact;
within the normal range or whether the output power is too low;
PT program;
NB-series Programmable Terminals Startup Guide Manual(V109)