以CAN為網路架構之分散式資料擷取系統

Abstract

工業界工具機的控制或生產流程系統的監控，長久以來都是以可程式邏輯控制器作集中式的掌控，在這种情況下控制器並不需要特別的綱路協定來取得系統的資訊。然而近來來隨著個人電腦與微控制器的普及以及使用者對系統功能與系統資訊的要求增加，分散式的綱路控制系統成為一種新的選擇，各種應用於分散式控制系統的綱路協定，稱為場或匯流排，也被提出以求達到更高的效能。本文以場域匯流排中之CAN綱路協定，建立一個分散式的資料擷取系統，並應用於XY平臺作教學式的控制。測試結果顯示在人為操縱或是訊號變化不是非常快（約小於10Hz）的監控場合下，本文之系統皆能符合所需。

Traditionally, the process control and monitoring in factories are carried out by the centralized programmable logic controller (PLC). Under this architecture, PLCs get system information from the devices directly without any communication network protocols. However, in recent years. the growing use of PCs and microcontrollers and the increasing demand for the system functions and information have made the distributed control system a new choice for control applications. Various network protocols which are called fieldbuses, have been proposed to obtain higher performance. In this thesis, a distributed data acquisition and control system based on one of these fieldbuses, the CAN, is implemented. In this system, an XY table is controlled by a human operator with a remote jog device which is connected to a PC using CAN protocol. Experimental results show that the system we established meets the control requirements when the system is operated by a human operator or when the signal frequency of the remote device is less than 10 Hz.