WOODWARD 8402-119伺服執行器,8402-119說(shuō)明書(shū)
實(shí)時(shí)數據原則上只在子系統網(wǎng)絡(luò )節中點(diǎn)共享，跨域數據需要事先合理配置
實(shí)時(shí)數據泛指動(dòng)態(tài)位號數據、各類(lèi)報警和事件等由DCS控制器產(chǎn)生的實(shí)時(shí)數據和事件。大多數DCS應用情況中，操作站（操作員）只關(guān)心本域（子工程）內的實(shí)時(shí)數據，并對其進(jìn)行及時(shí)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伺服執行器只需要查看部分接口界面數據即可。
以上描述的實(shí)際應用情況大大降低了構建大型實(shí)時(shí)數據網(wǎng)絡(luò )實(shí)際負荷，這意味著(zhù)大型DCS系統可以事先根據應用需求，拆分成若干個(gè)規模合理的子工程LAN。子工程數據庫相互獨立，通過(guò)事先的組態(tài)和配置，實(shí)現各子工程之間的數據交互，以及定期向管理層發(fā)送事先訂閱的各類(lèi)實(shí)時(shí)數據。
中控WebField ECS-700系統基于以太網(wǎng)的IEEE802.3Z實(shí)現對數據流的分區管理，應用組播管理和VLAN等成熟網(wǎng)絡(luò )技術(shù)，使得邏輯子工程內的網(wǎng)絡(luò )節點(diǎn)共享數據，同時(shí)隔斷子工程間無(wú)用的實(shí)時(shí)數據，防止網(wǎng)絡(luò )上出現數據泛濫，導致傳輸效率下降甚至網(wǎng)絡(luò )阻塞。
2.2 完善的網(wǎng)絡(luò )監控和在線(xiàn)防病毒方案
大型DCS系統的網(wǎng)絡(luò )故障案例大多數定性為工程階段的問(wèn)題，有工程設計的不合理、網(wǎng)絡(luò )部件的版本不兼容、工程實(shí)施時(shí)網(wǎng)線(xiàn)錯誤連接等。最常見(jiàn)的是網(wǎng)絡(luò )中毒，幾乎在所有的項目中都會(huì )發(fā)現各種級別的中毒情況，用傳統的病毒查殺技術(shù)費時(shí)費力，同時(shí)也會(huì )在一定程度上影響生產(chǎn)運行，更嚴重的甚至被迫停車(chē)檢修。WOODWARD 8402-119伺服執行器,8402-119說(shuō)明書(shū)因此，DCS制造商在設計大型工業(yè)控制網(wǎng)絡(luò )時(shí)，必須考慮完整全面的網(wǎng)絡(luò )監控和防毒方案。
中控在該項目中提供了全網(wǎng)診斷軟件VxNetSight，該軟件可實(shí)時(shí)觀(guān)測到每個(gè)網(wǎng)段，甚至每個(gè)網(wǎng)口上的數據負荷，以及各個(gè)節點(diǎn)的上線(xiàn)、故障、恢復情況，可以方便地設置各種負荷報警和流控限制，協(xié)助用戶(hù)正確高效地了解網(wǎng)絡(luò )運行情況，并及時(shí)采取相應的管理措施。
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)
