面向工业物联网的低功耗边缘层节点设计

　　一个工业物联网的架构（IIoT）应用程序使用了大量的网络传感器和执行器来监视和控制工业过程。在工业互联网参考架构中，这种智能连接元素的集合被称为边缘层，一个典型的边缘层节点位于或接近它所服务的机器。

　　边缘层节点的设计对设计者提出了一些挑战。随着传感器和执行器，每个节点还包括一个微控制器，电源电路，并与网络中的其他节点的串行通信链路接口。由于有数百或数千个节点，重要的是要保持成本和功耗最低。对于EMC产业环境是无情的，所以强大的防电磁威胁也是优先。

　　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）.