【正文】 re pushed to configured destinations like alarmfiles, (printer) queues or displays. SCADA Systems with DCS Features (Cube) The fact that the D/3 system mentioned above had some hard coded limitations with respect to the Y2K problem was forcing us to look for an upgrade or a replacement of the existing system. As a result of a call for tender the pany Orsi with their product Cube came into play [2]. The project included a plete replacement of the installed functionality. This included the D/3 as well as the integration of the DESY field bus SEDAC and the temperature conversion in VME. The project started promising. But soon technical and organizational problems were pushing the schedule to it?s limits which were determined by the HERA shutdown scheduled at that time. The final acceptance test at the vendors site showed dramatic performance problems. Two factors could be identified as the cause of these problems. The first one was related to the under estimated CPU load of the 6th grade polynomial temperature conversion running at 1 Hz. The second one was the additional CPU load caused by the plex functionality of the existing D/3 system. Here it was underestimated that each digital and analog input and output channel had it?s own alarm limits in the D/3 system. In a SCADA like system as Cube the base functionality of a channel is to read the value and make it available to the system. Any additional functionality must be added. Last not least the load on the work for polling all the alarm limits – typically for a SCADA system – was also driving the work to it?s limits. Finally the contract with Orsi was cancelled and an upgrade of the D/3 system was the only possible solution. It was finally carried out in march 2020. In any case it should be mentioned that the Cube approach had the advantage of a homogeneous configuration environment (for the Cube front end controllers) – pared with heterogeneous environments for ?pure? SCADA systems. SCADA (PVSSII) The H1 experiment at the HERA accelerator decided to use PVSSII for an upgrade of their slow control systems[3]. The existing systems were developed by several members of the H1 collaboration and were difficult to maintain. The 3 decision to use PVSS as a replacement was driven by the results of an extensive survey carried out at CERN by the Joint Controls Project [4]. PVSS is a ?pure? Supervisory And Data Acquisition System (SCADA). It provides a set of drivers for several field buses and generic socket libraries to implement munication over TCP/IP. The core element is the so called event manager. It collects the data (mostly by polling) from the I/O devices and provides an event service to the attached management services like: control manager, database manager, user interface, API manager and the built in HTTP server. The PVSS scripting library allows to implement plex sequences as well as plex graphics. Compared with other SCADA systems PVSS es with one basic feature: it provides a true object oriented API to the device?s data. One major disadvantage of SCADA systems is the fact that two databases, the one for the PLC and the one for the SCADA system must be maintained. Integrated environments try to overe this restriction. EPICS EPICS has emerged at DESY from a problem solver to a fully integrated control system. Starting from the data collector and number cruncher for the cryogenic control system, EPICS made it?s way to bee the core application for the DESY utility group. In addition it is used wherever data is available through VME boards or by means of Industry Pack (IP) modules. For those cryogenic systems which are not controlled by the D/3 system EPICS is used with it?s plete functionality. In total about 50 Input Output Controller (IOC) are operational processing about 25 thousand records. 1 EPICS as a SCADA System The utility group ( water, electrical power, pressed air, heating and air conditioning) is using a variety of PLC?s spread out over the whole DESY site. EPICS is used to collect the data from these PLC?s over Profibus (FMS and DP) and over Ether (Siemens H1 and TCP). The IOC?s provide the interfaces to the buses and collect the data. The built in alarm checking of the EPICS records is used to store and forward alarm states to the alarm handler (alh) of the EPICS toolkit. In addition tools like the channel archiver and the graphic display (dm2k) are used. The default name resolution (by UDP broadcast) and the directory server (name server) are used to connect client and server applications over TCP. All of these are basically SCADA functions. The textual representation of all configuration files ( for the IOC, the graphic tool, the alarm handler and the archiver) provides a flexible configuration scheme. At DESY the utility group has developed a set of tools to create IOC databases and alarm configuration files from Oracle. This way the controls group provides the service to maintain the EPICS tools and the IOC?s while the users can concentrate on the equipment being controlled. 4 2 EPICS as a DCS System Besides the basic ponents of a SCADA system EPICS also provides a full flavoured Input Output Controller (IOC). The IOC provides all of the function a DCS system requires, such as: a standard set of properties implemented in each record, built in alarm checking processed during the execution of each record。經(jīng)濟(jì)因素使決定趨向于協(xié)同工具。此外，在實(shí) 現(xiàn)對(duì)復(fù)雜的低溫冷藏系統(tǒng)的開(kāi)閉過(guò)程中，頻率項(xiàng)目顯得尤為重要。在展示端和 I / O端擴(kuò)展此系統(tǒng)的可能將有助于解決日益增加的 HERA試驗(yàn)控制的要求。但是因?yàn)?HERA 試驗(yàn)原定時(shí)間是有限制的，所以技術(shù)問(wèn)題和組織問(wèn)題也迫使計(jì)劃提前。 最后，與 Orsi 公司的合同被取消了。其核心元素叫做事件管理器。從成為低溫控制系統(tǒng)的數(shù)據(jù)收集器和數(shù)量控制器， EPICS成為了德國(guó)電子同步加速器研究所公用事業(yè)集團(tuán)使用的核心系統(tǒng)。所有這些都是基本的 SCADA功能。后者大大降低了 信息擁堵的情況。但是，在極少數(shù)情況下，只通過(guò)商業(yè)的立場(chǎng)時(shí)難以回答的。對(duì)顯示和控件的屬性的支持是必不可少的。所有 SCADA系 統(tǒng)在市場(chǎng)商業(yè)運(yùn)作中是可行的。開(kāi)放 API 或腳本支持有時(shí)有助于整合用戶的硬件。運(yùn)行時(shí)環(huán)境取決于相關(guān)代碼。 前端控制器： 對(duì)控制系統(tǒng)的核心要素之一，是前端控制器。此外，定期執(zhí)行一個(gè)確定功能的基本特征也讓他們通