Study And Design Of Hydraulic Data Acquisition System Based On CPLD

Data acquisition system is an essential section of the signal and information processing. It offers data for equipment running in the course of monitoring and fault diagnosis of hydraulic device. And the result of diagnosis is directly depended on the acquisition technique. Thus, a high-powered hydraulic DAQ system will make equipment maintenance informational and intelligent, and will farther largely prevent the loss of money and casualties that may be caused by failure of hydraulic equipments.According to the characteristic of hydraulic equipment and the requirement of fault diagnosis, this thesis develops the hardware and software system based on the USB2.0 communication technology and virtual instrument technology. This system adopts FX2 plus CPLD architecture and pipelining collection technology, which has friendly interface and costs a little. The DAQ system realizes functions of real time data acquisition, display, storage and digital filtration, providing accurate and effective data for monitoring and diagnosis. The key point of this thesis is as follows:(1) The design of hardware circuits and CPLD(Complex Programmable Logic Device) program divides real time DAQ process into three modules including A/D conversion, data buffer storage and data transmission. It's executed under the control of CPLD hardware and the MCU (Micro Control Unit), to realize high-speed data acquisition at low main-frequency CPU.(2) According to the characteristics of FX2 (CY7C68013) structure, the firmware is programmed by Keil C51. It completes the main control of DAQ system and USB2.0 communication.(3) In the aspect of software, application programs and USB drive based on LabVIEW are designed adopting NI-VISA. Through keyboard and mouse, the control and processing of data acquisition can be achieved effectively.(4) At last, precision test and dynamic application test have been done for the whole system experiment.The experimental results prove that the application program works exactly well under our high-speed hydraulic DAQ system, and the data acquired can reflect the precise condition of the device, which is up to the requirement in design of acquisition speed and precision.