(例如S-232C或RS一485串行口)将触摸信息传送到PLC，从而得到输入的信息。 The basic principle of a touch screen is as follows: The essence of a touch screen is a sensor. When a user touches the touch screen mounted on the display with a finger or other object, the coordinates of the touched position are detected by the touch screen controller and communicated through a communication interface (such as S-232C or RS 485 serial port) will transmit the touch information to the PLC to get the input information.
Infrared touch screen:
The infrared touch screen uses a dense infrared matrix in the X and Y directions to detect and locate the user's touch. The infrared touch screen is equipped with a circuit board frame on the front of the display. The circuit board arranges infrared transmitting tubes and infrared receiving tubes on the four sides of the screen, which correspond to the infrared matrix that crosses vertically. When the user touches the screen, the finger blocks the two infrared rays passing through the position, so that the position of the touch point on the screen can be determined. The external touch screen is a highly integrated electronic circuit integration product. The infrared touch screen contains a complete integrated control circuit, a set of high-precision, anti-interference infrared transmitting tubes and a set of infrared receiving tubes. The two opposite directions installed on the highly integrated circuit board form an invisible infrared Raster. The intelligent control system embedded in the control circuit continuously pulses the diode to form an infrared polarization beam grid. When a touch object such as a finger enters the grating, the light beam is blocked. The intelligent control system will detect the change in the loss of light and transmit a signal to the control system to confirm the X-axis and Y-axis coordinate values.
Capacitive touch screen:
The touch screen is a transparent absolute positioning system. First of all, it must be transparent. The problem of transparency is solved through material technology. The second is that it can give the absolute coordinates of where the finger touches, and the mouse belongs to a relative positioning system. The characteristic of the absolute coordinate system is that the coordinates of each positioning have nothing to do with the coordinates of the previous positioning. The touch screen is physically a set of independent coordinate positioning systems, and the position of each touch is converted to the coordinates on the screen.