WOODWARD 8402-119伺服執(zhí)行器,8402-119說明書
實(shí)時數(shù)據(jù)原則上只在子系統(tǒng)網(wǎng)絡(luò)節(jié)中點(diǎn)共享，跨域數(shù)據(jù)需要事先合理配置
實(shí)時數(shù)據(jù)泛指動態(tài)位號數(shù)據(jù)、各類報(bào)警和事件等由DCS控制器產(chǎn)生的實(shí)時數(shù)據(jù)和事件。大多數(shù)DCS應(yīng)用情況中，操作站（操作員）只關(guān)心本域（子工程）內(nèi)的實(shí)時數(shù)據(jù)，并對其進(jìn)行及時和必要的處理。而對上下游的關(guān)聯(lián)裝置、公用工程，WOODWARD 8402-119伺服執(zhí)行器只需要查看部分接口界面數(shù)據(jù)即可。
以上描述的實(shí)際應(yīng)用情況大大降低了構(gòu)建大型實(shí)時數(shù)據(jù)網(wǎng)絡(luò)實(shí)際負(fù)荷，這意味著大型DCS系統(tǒng)可以事先根據(jù)應(yīng)用需求，拆分成若干個規(guī)模合理的子工程LAN。子工程數(shù)據(jù)庫相互獨(dú)立，通過事先的組態(tài)和配置，實(shí)現(xiàn)各子工程之間的數(shù)據(jù)交互，以及定期向管理層發(fā)送事先訂閱的各類實(shí)時數(shù)據(jù)。
中控WebField ECS-700系統(tǒng)基于以太網(wǎng)的IEEE802.3Z實(shí)現(xiàn)對數(shù)據(jù)流的分區(qū)管理，應(yīng)用組播管理和VLAN等成熟網(wǎng)絡(luò)技術(shù)，使得邏輯子工程內(nèi)的網(wǎng)絡(luò)節(jié)點(diǎn)共享數(shù)據(jù)，同時隔斷子工程間無用的實(shí)時數(shù)據(jù)，防止網(wǎng)絡(luò)上出現(xiàn)數(shù)據(jù)泛濫，導(dǎo)致傳輸效率下降甚至網(wǎng)絡(luò)阻塞。
2.2 完善的網(wǎng)絡(luò)監(jiān)控和在線防病毒方案
大型DCS系統(tǒng)的網(wǎng)絡(luò)故障案例大多數(shù)定性為工程階段的問題，有工程設(shè)計(jì)的不合理、網(wǎng)絡(luò)部件的版本不兼容、工程實(shí)施時網(wǎng)線錯誤連接等。最常見的是網(wǎng)絡(luò)中毒，幾乎在所有的項(xiàng)目中都會發(fā)現(xiàn)各種級別的中毒情況，用傳統(tǒng)的病毒查殺技術(shù)費(fèi)時費(fèi)力，同時也會在一定程度上影響生產(chǎn)運(yùn)行，更嚴(yán)重的甚至被迫停車檢修。WOODWARD 8402-119伺服執(zhí)行器,8402-119說明書因此，DCS制造商在設(shè)計(jì)大型工業(yè)控制網(wǎng)絡(luò)時，必須考慮完整全面的網(wǎng)絡(luò)監(jiān)控和防毒方案。
中控在該項(xiàng)目中提供了全網(wǎng)診斷軟件VxNetSight，該軟件可實(shí)時觀測到每個網(wǎng)段，甚至每個網(wǎng)口上的數(shù)據(jù)負(fù)荷，以及各個節(jié)點(diǎn)的上線、故障、恢復(fù)情況，可以方便地設(shè)置各種負(fù)荷報(bào)警和流控限制，協(xié)助用戶正確高效地了解網(wǎng)絡(luò)運(yùn)行情況，并及時采取相應(yīng)的管理措施。
migration path and protects users' investment in I / O and application development.
3. Solutions and main products of PAC control technology
From the definition, we can see that PAC is actually a systematic concept. It includes two parts: integrated software platform and hardware platform based on open modular structure. The solution of PAC technology also focuses on these two aspects.
Generally speaking, there are two ways to provide PAC software: Software Based on PLC control and software based on PC control.
1) Software scheme based on PLC control. Most PLC manufacturers build PAC software by adding new functions to the existing scanning architecture. These new functions include Ethernet communication, motion control and advanced algorithms. Usually, they will retain the familiar programming mode of PLC and the inherent characteristics in logic and control. Therefore, this kind of PAC software is usually designed for special types of applications.
2)
