C/S结构网络的两种硬件,通常称为客户PC和服务器。客户PC在中央控制室,而服务器放在安全的地方。DCS操作站死机的原因错综复杂。本文仅限于分析由于采用C/S结构引起的死机原因,有两种情况:
控制器、服务器和客户机三者之间的连接有两种情况:一是DCS控制器有以太网接口,三者用以太网交换机来连接。交换机有多种端口,每个端口数据传输速率可以不等。端口数量由连接的计算机台数决定。交换机主要指标是背板宽度和存储器大小。如果采用以太网电缆如10BASE、100BASE等的速率都可传输,如采用5类线只能是10BASE。在图2以太网的连接是星型。使用离散的
电缆将每台计算机连接到中央连接点,通常称为网络集线器。每台计算机使用独立电缆,连接失败只影响有关的单台计算机,其他计算机可继续运行。如果各台机器适配器速率相同,以太网星型连接通常使用10BaseT电缆。Two kinds of hardware of c/s structure network, usually called client PC and server. The client PC is in the central control room and the server is in a safe place. The causes of DCS operation station crash are complicated. This article is limited to analyzing the causes of the crash caused by the c/s structure. There are two cases:
There are two kinds of connections among controller, server and client: one is that DCs controller has Ethernet interface, and the three are connected by Ethernet switch. The switch has a variety of ports, and the data transmission rate of each port can be different. The number of ports is determined by the number of computers connected. The main indicators of the switch are the backplane width and memory size. If Ethernet cables such as 10base and 100base are used, the rate can be transmitted. If category 5 cable is used, it can only be 10base. In Figure 2, the Ethernet connection is star shaped. Use discrete
Cables connect each computer to a central connection point, commonly referred to as a network hub. Each computer uses an independent cable. The connection failure only affects the relevant single computer, and other computers can continue to run. If each machine has the same adapter rate, the Ethernet star connection usually uses a 10baset cable.