Research On Stream-based Signal Acquisition System

The data acquisition device of the measurement signal acquisition and analysis systemgradually breaks away from the host computer and the DAQ (Data Acquisition) type changesfrom the slot-typed ISA, PCI and PXI bus to LXI, USB, wireless and Ethernet and so forth,due to the development of the mobile internet, the mobilized and networked devices. Theupper-position computer and lower-position computer of acquisition and analysis systemhave a separate CPU, with the existence of peer relationship. However, this method hasdrawbacks: user must be familiar with the acquisition driver before using the hardware and itis not convenient to use a variety of driver interfaces for different communication interfaces.This paper aims at rising up a measurement signal acquisition and analysis system basedon stream, which has the advantage of freedom of DAQ driver, convenience to use, andsupporting multi-platform client and communication interface. The principal computer andthe DAQ device communicate with each other by the way of stream in this system.In the first section, the purpose, the significance and the research background arediscussed, with it the concept of a novel signal measurement DAQ and analysis system isproposed, and the literature review and practical application are also introduced.Then, the overall architecture of the new system is proposed and the communicationfeature of the concept of current is further explained through specific programming models ofthe USB, the serial port and the network communication. Furthermore, a study of theadvantages and disadvantages of the standard VISA and SCPI instrument communicationprotocol is put forward and the concept of the user-defined DAQ communication protocols isproposed, including the binary coding and the ASCII.Next, the server and client software programme in different platform are designedmethod, under the structure of the signal acquisition system based on stream.Finally, according to the structure of measurement signal acquisition and analysis systembased on stream, acquisition card firmware is designed to support stream. Besides, use streamfunctions of C++, Matlab, Labview, HTML5language to achieve the control of theacquisition card. The feasibility of no driver in the system is confirmed under the platform ofthe rotor test rig and a double-tank level control system.