Design And Realization Of Multi Function Data Acquisition System Based On EtherCAT Network

In recent years, various scientific researches and engineering applications of ocean engineering are overwhelming with the development of national strategy for utilization of ocean resources, and more and higher requirements are proposed for experimental research in ocean engineering, such as larger numbers and more types of sensors, more precise and accurate test data, higher real-time and speed for data acquisition. However, traditional testing methods are difficult to meet the requirements. Therefore, it is necessary to develop new multifunctional data acquisition systems for ocean engineering tests by using the popular industrial Ethernet fieldbus control technology.This paper presents a multifunctional data acquisition system based on EtherCAT for actual requests of experimental measurements and control in the ocean engineering laboratory. The system containing a single master and multi-slavers is developed based on the EtherCAT protocol which was proposed by Beckhoff Corporation. It can meet the requirements of multi-types sensors, large data volume and high speed sampling. Its master only needs a PC with Windows XP and a standard Ethernet card. The EtherCAT slave station takes PIC SCM as its control core, which runs the embedded system program and controls the choice of multi-channel analog signals, A/D conversion, data exchange with the slave network controller ET1100 and communication with the master.In this paper, we first describe the EtherCAT protocol specification and the communication principle, which indicate that EtherCAT is well suited for our research. Then the overall design requirement for the networked data acquisition system is presented, the design and implementation methods for each component of the system are given in detail. Finally, the system is tested carefully in laboratory.The actual test results demonstrate that the proposed networked multi-function data acquisition system can meet the operating requirements for scientific and engineering experiments in ocean engineering area, and the research work has attained the desired goal.