面向工業物聯網的低功耗邊緣層節點設計

　　一個工業物聯網的架構（IIoT）應用程序使用了大量的網絡傳感器和執行器來監視和控制工業過程。在工業互聯網參考架構中，這種智能連接元素的集合被稱為邊緣層，一個典型的邊緣層節點位于或接近它所服務的機器。

　　邊緣層節點的設計對設計者提出了一些挑戰。隨著傳感器和執行器，每個節點還包括一個微控制器，電源電路，并與網絡中的其他節點的串行通信鏈路接口。由于有數百或數千個節點，重要的是要保持成本和功耗最低。對于EMC產業環境是無情的，所以強大的防電磁威脅也是優先。

　　IO-Link overview

　　IO-Link （IEC 61131-9） is a point-to-point serial communication protocol optimized for intelligent Edge Tier nodes that contain sensors， actuators， and low-power microcontrollers. In its basic form it is a three-wire connection that can switch both analog and digital signals （8， 12 and 16 bits）。 It has wide industry support due to its simplicity， intelligence， efficiency， configurability and ability to provide more information and control.

　　For example， it uses standard connectors and cables， eliminating custom connections. Using IO-Link， developers can identify devices and perform automated re-parameterization on the fly. Its Service Protocol Data Units （SPDUs） give access to detailed sensor and actuator status， from device type and ID numbers， to full diagnostics.

　　In a typical industrial installation， multiple IO-Link Masters operate actuators and collect data from sensors; they can also dynamically reconfigure sensors and actuators， known as “devices” in IO-Link terminology （Figure 1）.