Design and implementation of a six-channel embedded system for reading touch sensors

Touch Sensors are used for precisely measuring displacements of the object of Taiwan Photon Source (TPS) Girder Control System (GCS). Therefore, a six-channel embedded system is designed for reading touch sensors with ENDAT 2.1 protocol. It is a portable and reliable equipment for simultaneously reading six touch sensors via the combination of digital implementation in a Field Programmable Gate Array (FPGA) chip and control software in a single-board computer. Thus, the embedded system can offer six input channels for touch sensors and its sampling rate reaches up to 1 KHz per channel. The embedded system also provides a web page to indicate the measurements and communicates between other devices by Experimental Physics and Industrial Control System software (EPICS). Finally, the six-channel embedded system for reading touch sensors reaches the satisfactory stability and high-speed transmission and is an easy-to-use multi-channel reader. This paper represents all design processes and structures of the six-channel embedded system.