The Research And System Design Of ASI (Actuator-Sensor Interface)

The Actuator-Sensor-Interface, abbreviated ASI, is a system introduced in 1994, with which simple sensors, actuators, and etc., are linked with the first control layer in industrial automation. Because of his structure simplicity and easy operation, it occupies 60% quota in European markets. However, such field of out country leaves far behind the world level. In order to develop our own ASI products, I take the research of independent-developing ASI system as my master thesis.The thesis first illustrates the characteristics and ASI system, then analyzes its transmitting system in detail and presents its design requirements according to its electric and functional specification. The Special IC, A2SI, is the core unit of transmission module, which lies in the bottom of the network structure. So the thesis introduces the framework and frequently emergent problems of it specially. On the basis of thorough study of ASI industrial complete specification, I begin to design the slave and the master and apply them to practice. The products of the work go as followed: â‘  develope the uniform ASI slave module, which could be linked with many kinds of sensors. The condition of slaves can be configured by the master. â‘¡ develope special transmitter for ASI master, which needs only two control wires. Design the encoder and decoder of Manchester Code, which can encode and decode the Manchester Code of 167kbps. â‘¢ develop the executer for ASI Master, which could download the user program for control. The program memory is divided into two areas: one is system area, the programs in which are written by the designer; the other is user area, the programs in which are written by the user. User programs can be downloaded from the monitor computer, and can call system functions of system area. â‘£ develope the user interface on PC, by which the user can monitor and configure the system. Design the on-line downloader based on Serial Port Communication. The user can download hisprograms into the executer.The other part of the thesis probes into the problems unsolved in ASI system up to now. The current ASI special IC can only transmit 4 bit data of switch sensors, I design special slave interface for transmitting more bit data from analog sensor. The master transmits control signal and data signal based on IC separately. After the analysis of the system, I present the work flow char and circuits. At the present stage, ASI system adopts only wire transmission methods. The thesis discusses the promising wireless transmission media, Bluetooth, for ASI system. It elucidates the possibility of combining these two systems based on their similar running principles, and presents the logic design chart. Finally, I summarize the trends of Fieldbus and its technique problems which need to be solved.