P0918KG模块备件使用参数

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近来，由于MIS系统需从DCS中读取生产实时数据。在网络中接进动态数据服务器，有的采用DDE方式，在读取数据较多情况下（如3000点），由于DDE消耗资源较多，网络堵塞现象就变得十分频繁，并使得各种人机界面的节点死机现象变得严重。
网络堵塞现象的严重程度与多种因素相关。从操作站取数据，采用DDE方式，如果取的数据

在500点以下，问题还不算太大。如果取几千点数据，操作站死机几乎是必然的。如果把节点连到DCS的通信网络上，从网络接口取数据，情况要好一些。
控制器把数据送到接口，人机界面从网络接口读取数据应遵守网络通信协议。网络物理结构有环型和总线型两种，总线网络在逻辑上也是环型的。星型网络只用于小系统（100个I/O点内）。常用通信协议是广播式，网络上的节点只要把数据送到网络上，它就要不断广播数据，需要数据的节点就接收数据。广播式协议的网络除这种方式外，还有一种方式：一个节点向网上其他节点问询数据，如其他节点没有，它就反复进行问询直至读取到这个数据。如果网络上根本没有这个数据，就会造成网络堵塞。
为使运行人员熟练DCS操作站的操作，可采用仿真系统，了解DCS的键盘，以减少误操作引起死机；也可了解操作站死机情况。
在DCS运行时间较长的情况下，组态只加不减，有一部分组态实际上已没有与真正的I/O点相连，与控制无关。在工程师站的用户应用程序中有这样的I/O点。动态数据服务器接入时，欲将DCS上所有数据点都读上去，因其中有大量数据点无效而造成网络堵塞，所以人机界面就发生死机。这时可用逆向工程师站读取控制器中的组态，与正向工程师站的内容进行比较，删除无效点，就可避免网络堵塞。

Recently, MIS system needs to read real-time production data from DCS. Some dynamic data servers are connected to the network in DDE mode. In the case of more data reading (such as 3000 points), the network congestion becomes very frequent due to more resources consumed by DDE, and the node crash of various human-computer interfaces becomes serious.
The severity of network congestion is related to many factors. Data is fetched from the operation station in DDE mode. If the fetched data
Below 500 points, the problem is not too big. If several thousand data points are taken, it is almost inevitable that the operation station will crash. It is better to connect the node to the DCS communication network and get data from the network interface.
The controller sends the data to the interface, and the man-machine interface reads the data from the network interface in accordance with the network communication protocol. The physical structure of the network can be divided into ring type and bus type, and the bus network is also ring type logically. Star network is only used for small systems (within 100 i/o points). The common communication protocol is broadcast. As long as the node on the network sends the data to the network, it will continuously broadcast the data, and the node that needs the data will receive the data. In addition to this method, there is another method in the broadcast protocol network: a node asks other nodes on the network for data. If other nodes do not have data, it will repeatedly ask until it reads the data. If there is no such data on the network, it will cause network congestion.
In order to make the operators familiar with the operation of DCS operation station, the simulation system can be used to understand the DCS keyboard, so as to reduce the crash caused by misoperation; You can also learn about the operation station crash.
When DCS runs for a long time, the configuration is only increased but not decreased. Some configurations are actually not connected to the real i/o points and have nothing to do with control. There are such i/o points in the user application of the engineer station. When the dynamic data server is connected, it wants to read all the data points on the DCS. Because a large number of data points are invalid, the network is blocked, so the man-machine interface crashes. At this time, the reverse engineer station can be used to read the configuration in the controller, compare it with the contents of the forward engineer station, and delete the invalid points to avoid network congestion.