Design And Research Of Industrial Sensor Networks Based On Fiber Transmission

With the development of modern science and technology, demand for data transmission and exchange has grown significantly. As a result, the requirement for data speed is becoming higher and higher. Especially in the industry field monitoring, kinds of sensor data has been increasing fast. Remote and real-time transmission should also be concerned in many applications. In some severe industry environment, the traditional sensor network based on cable transmission would be invalid. The maintenance costs will be high. With the development of intelligent sensor and fiber technology, it is easier to construct sensor network system based on optical fiber transmission. Fiber transmission networks bring about great convenience for the sensor network due to its excellent capability of networking. Fiber transmission system has lots of advantages, such as long transmission distance, high information content, strong anti-interference ability, pretty good confidentiality and so on. So the fiber transmission networks could be used to some industry fields, replacing the cable networks.Industry sensor system based on fiber transmission is designed according to the long distance and high speed transmission of multi-channel sensor data in the bad environment. The system can realize the analog signal and digital signal acquisition. Then the multi-channel sensor signals are transmitted via single fiber by using time division multiplexing technology. FPGA chip is selected as core control device. The system realizes the data acquisition, analog-digital conversion and data transmission under the control of FPGA. CAN network protocol was designed in FPGA, with which the data acquisition nodes can communicate with CAN field bus instruments; the signals transmit through fiber was coded with CMI; then the synchronous clock can be extracted from the signals before decoding the received data. The valid data is transmitted to next nodes through fiber or CAN port, or to PC by serial communicate port.There are several advantages in this design such as high integration, simple wiring, easy to upgrade and strong anti-interference ability. By using FPGA chip, the data processing rate is increased. The hardware circuit debugging and data transmission experiments in this fiber network were performed, which results showed reliability of the data transmission process.