Development of Factory Automation WLAN System Compatible with Asynchronous Industrial Ethernet

In this paper, we propose a design of asynchronous communication for an industrial wireless LAN system. In our design, MAC is synchronous multi-user round-robin transmission protocol. Low overhead Packet Division Multiple Access scheme is utilized for Multi-user Downlink transmission up to 80 MHz, while Frequency Division Multiple Access is employed for the uplink transmission. The designed of PHY system is developed based on a fast and deterministic communication featuring the synchronous multi-user system. In this paper, the industrial robots are not only controlled by synchronous communication but also by asynchronous communication via our industrial WLAN (iWLAN) system. This paper presents the hardware and software cooperative design. In the verification, up to 10 motors can be controlled by our iWLAN system by asynchronous communication, and the delay of each robot measured is 188 mu s on average. Besides, the time synchronization captured by oscilloscope is from 40 to 100 ns as in our target.