Design and Implementation of EtherCAT Master of Gyrowheel under RTX System

A gyrowheel is a new type of equipment that integrates spacecraft attitude control and measurement functions. The upper and lower computers of the existing gyrowheel prototype system communicate with each other through Advantech PCL boards. The cost is high and the structure is complicated. This article designs and implements EtherCAT master of gyrowheel under RTX system with lower cost and simpler structure. First, the operation principle and data frame structure of the EtherCAT communication protocol are analyzed. Then, the EtherCAT master under the RTX system was designed, including the network card driver module, configuration module, and data communication module. Among them, the network card driver module is implemented by modifying the official open source network card driver provided by IntervalZero, which can configure the network card to send and receive data; the configuration module configures the registers of the slave by constructing-sending and receiving data frames, and switches the slave from the Init state to the Op state; the data communication module periodically collects gyrowheel data information through the timer and outputs control amount. Finally, a system experiment platform was established to verify that EtherCAT communication can be performed between the master and slave.