Touch screen technology is following the keyboard, mouse, handwriting board, voice input after the most common people easy to accept the computer input method. The use of this technology, the user as long as the finger gently touch the computer display on the symbols or text can be realised on the host operation, thus making human-computer interaction more straightforward. This technology greatly facilitates the user, is extremely attractive new multimedia interactive devices.
The essence of the touch screen is the sensor, which consists of touch detection components and touch screen controller. Touch detection components installed in front of the display screen, used to detect the user's touch location, acceptance of the touch-screen controller; touch-screen controller's main role is to receive touch information from the touch-point detection device, and convert it into contact coordinates sent to the CPU, and at the same time, can receive commands sent from the CPU and to be implemented.
Touch screen system generally includes two parts: touch detection device and touch screen controller. Touch detection device installed in front of the display screen, used to detect the user touch position, and then the information will be transmitted to the touch screen controller; touch screen controller's main role is to receive touch information from the touch point detection device, and convert it into contact coordinates, judge the significance of the touch sent to the PLC, which at the same time can receive commands sent by the PLC and to be implemented, such as dynamic display of switching and analogue quantities. It can also receive commands from PLC and execute them, such as dynamic display of switching and analogue quantities.
Technical characteristics:
From the technical principle point of view, the touch screen is a set of transparent absolute coordinates positioning system, first of all, it must ensure that it is transparent, so it must be through the material science and technology to solve the problem of transparency, such as digitisers, writing boards, lift switches, they are not a touch screen; Secondly, it is an absolute coordinate, the finger touches where it is, no need for a second action, unlike the mouse, is a set of relative positioning of the system, we can Note that the touch screen software do not need a cursor, a cursor in turn affects the user's attention, because the cursor is for the relative positioning of the device, the relative positioning of the device to move to a place where the first thing you need to know where you are, in which direction to go, and every now and then you need to give the user feedback on the current position to not be biased. These take the absolute coordinates of the positioning of the touch screen are not required; and then the second is able to detect the finger touch action and determine the finger position.