Abstract:

High performance acoustic logging tool consists of a number of parts,and its structure is complicated.Interface among tools,internal interface based on control commands and local high-speed data transmission interface are all key problem in technology in the design of the tool.Down-hole tools are connected each other by Controller Area Network.Special serial command bus completes interface between main controller and controlled units,and the control bus is applied to connect circuit boards and seal electronic cartridges.Complex programmable logic devices(CPLD) in controlled units decode receives commands and configure parameters accordingly.The rate of control bus is 100kbps.High-speed data transmission interface between boards is composed of sending controller and receiving controller,the two controllers are all accomplished by CPLD and data transmission rate is 5 Mbps.Serial data transmission mode is simple and reliable,it can be isolated and shielded easily,and the transmission rate can satisfy practical applications.Acoustic logging tools,based on the serial data transmission,were tested in several test wells and exploration wells of petroleum production field,and feasibility and reliability of serial data transfer are validated.

Key words: acoustic logging tool, serial bus, control command, CPLD, interface