Advantech FPM-8192V/8232V - Manual (Page 13)

5 FPM-8192V/8232V User Manual
Chapter 1
G
eneral
Information
1.2.2 SecureTouch Surface Wave Touchscreen (Optional 2)
Introduction to SAW Touchscreen
The surface wave is the optical standard of touch. Its pure glass construction pro-
vides superior optical performance and makes it the most scratch-resistant technol-
ogy available. It's nearly impossible to physically "wear out" this touchscreen.
The touch have a glass overlay with transmitting and receiving piezoelectric trans-
ducers for both the X and Y axes. The touchscreen controller sends a five-megahertz
electrical signal to the transmitting transducer, which converts the signal into ultra-
sonic waves within the glass. These waves are directed across the front surface of
the touchscreen by an array of reflectors. Reflectors on the opposite side gather and
direct the waves to the receiving transducer, which reconverts them into an electrical
signal—a digital map of the touchscreen surface.
When you touch the screen, you absorb a portion of the wave traveling across it. The
received signal is then compared to the stored digital map, the change recognized,
and a coordinate calculated. This process happens independently for both the X and
Y axes. By measuring the amount of the signal that is absorbed, a Z-axis is also
determined. The digitized coordinates are transmitted to the computer for processing.
Brief Specifications
Subject Details
Input Method Finger or gloved hand (cloth, leather, or rubber) activation
Positional Accuracy Standard deviation of error is less than 0.080 in. (2 mm)
Resolution Touchpoint density is based on controller resolution of 4096 x
4096, plus 255 levels corresponding to touch pressure
Touch Activation Force Typically 2 to 3 ounces (55 to 85 grams)
Light Transmission Up to 90% per ASTM D1003-92