Omron NB3Q-TW_B Startup Manual page 120

4
Why is the PT touch-control not responding or insensitive
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 is damaged or the touch-control circuit suffers a poor contact;
Solutions:
(a) Resolve the communication problem;
(b) Try out a touch-control calibration;
(c) Send it back to the factory for tests.
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, quotations, 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 OMRON's customer service center.
6
PT white screen and flickering screen
The causes of a white screen or a flickering screen: the ambient temperature exceeds the
range specified on the PT nameplate, or the liquid crystal is damaged.
Solutions: Check the ambient temperature and compare it with that specified on the PT, or
contact OMRON's customer service center.
7
The serial port gets heated when the PT communicates with other devices
Check the grounding of the PT and other communication devices. If the grounding is not
shared, there is a possible significant voltage difference between the devices, leading to a
heavy current, thus causing a heated serial port.
NB-series Programmable Terminals Startup Guide Manual(V109)
respond;
characteristics may cause the touch-control to be unable to respond;
within the normal range or whether the output power is too low;
PT program;
6 Maintenance and Troubleshooting
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