Research On Ultrasonic Measurement System For Water-Level Based On CPLD

Using ultrasonic to measure length, distance, displacement has a long history. Ultrasonic measuring has many advantages like directional emission easy, good direction, powerful control, and don't requiring direct contact with the object to be a kind of ideal measuring the water level. Ultrasonic measurement for water level at home and abroad mainly focused on how to improve the accuracy of distance.Currently, most of the measuring systems on the market are the traditional MCU system as the main control module to carry out the design. The design of this thesis is conducted with the water level ultrasonic distance measurement system has required a high clock frequency and strong control of timing. Complex programmable logic device (CPLD) as a logic control device, provides a new technique for the design of high-performance ultrasonic measuring. CPLD is programmed by VHDL hardware description language, that has a strong combination of timing control and logic ability, in particular for high-speed interface, communication interface can be different protocols at different rates of coupling and bridge, the perfect combination of ultrasonic distance measurement can be accomplished by system of measuring the water level.This research on Ultrasonic measurement system for water-level based on CPLD described main content as follows:(1) Described the related technology about ultrasonic measurement for water level; described the system design of ultrasonic measurement for water level; described the environment impact of the measurement accuracy;(2)Described hardware design, including the ultrasonic transmitter and receiver circuit design, CPLD design, automatic compensation correction circuit and display circuit design;(3)Compiled CPLD by using VHDL language programmed the control module, and debugged the various modules within the CPLD in the QuartusⅡ; made the experimental test platform, completed debugging of the system and the performance analysis.This design of ultrasonic measurement for water level system in the output frequency, resolution, repeatability, precision and other major technical indicators than the current measurement water level systems on the market increased by 1-2 orders of magnitude, expanded the application field of ultrasonic measurement greatly.