Design Of Acoustic Well-Logging Data Interface And Data Transmission System Based On CAN Bus

Acoustic logging system has realized data communication by many kinds of communication standard, such as serial port, PCI bus, USB bus etc. However, these communication methods are limited in speed, distance, reliability or easy-to-use requirement. As a distributed and real-time industrial field bus,CAN bus has high reliability, fast communication rate, long transmission distance and other advantages. It can be used to construct data communication system. In this paper, CAN-bus technology is adopted to transmit the acoustic logging data. The downhole acoustic logging data is transferred to the ground data processing system by the well-logging cable. Then the data (including Martin-decker depth data) is transmitted to the computer by CAN bus, which is employed to achieve the downloading of the computer command and the uploading of the acquisition data . The whole system also has a characteristic of better extendibility. The reliability and the anti-jamming measures of the designed system are also studied in this paper. The main research work of the thesis is as follows:First, the ground interface circuit of the downhole acoustic logging data transmission is designed. The downhole acoustic logging circuit can upload data and receive command from the ground system in Manchester code by well-logging cable. And in the ground system, the data and upper computer command can be transported by CAN bus.Second, the Martin-decker signal acquisition and processing circuit is designed and realized. It can transport the data to upper computer by CAN bus and achieve the measurement of well depth.Third, the main PC computer (main node) is connected to the CAN bus by the USB-CAN adapter, and has realized the real time acquisition and monitoring of the acoustic logging data and well depth data.The preliminary experimental results show that the system has realized the real time transmission of acoustic logging data and the precise measurement of well depth. The reliable CAN network is constructed in the system. The system is of great application value.