工業觸摸屏時代的到來

　　有開關和按鈕，由車輪和滑塊驅動的線性或旋轉電位器，工業控制面板是機械運動場。作為機械，他們有可能成為問題的根源，從焊接接頭到運動部件。為一組特定的控制任務而構建，這些板很難，如果不是不可能的話，可以重新配置。他們不容易學會如何使用，而且對于復雜的操作，常常伴隨著屏幕顯示設備狀態。

　　今天，這些都是消失的品種。相反，新的安裝完全是固態的，它們使用GUI（圖形用戶界面）驅動的顯示屏幕上的觸摸屏。通過改變屏幕圖像，觸摸屏上面的區域可視地鏈接到不同的功能。這意味著，以及可重構，系統可以指導用戶通過操作，也許在啟動或關閉，也許當一些不尋常的事情發生。雖然這種方法的優點是界面更健壯、更易于清洗和更廣泛的環境耐受性，但它的代價是：軟件和復雜的軟件。

　　Of course， the different equipment， controlled by the screens， is itself managed by processors and software. The individual pieces of machinery communicate with each other and the overall system controller over some kind of bus， like CAN or Industrial Ethernet. Usually there is a strong element of real-time control needed and the applications may be safety critical， so the architecture of the entire system needs to be designed to segregate the touch screen controller and GUI from the overall system data， except through a secure defined interface. In this way， any issues with the GUI software will have no effect on the safety of the overall system or individual pieces of equipment.

　　This segregation might be caused by running all the GUI and touch screen activities on a separate processor running a general purpose operating system while the control activities operate on a real time operating system on its own processor. The processors might be physically separate devices， separate cores on a single chip or virtual cores created by virtualization software.

　　In this article， although we will be looking at physically separate controllers， much of the discussion will also be relevant to a touch screen controller running in a virtual core.