在熱工自動化領(lǐng)域，主廠房控制系統(tǒng)基本上毫無例外地使用DCS。而在輔助車間才使用PLC。其主要原因是早期的DCS系統(tǒng)非常昂貴，人們認(rèn)為輔助車間的運行可以間斷，可靠性要求不是很高，且模擬量控制要求較少，從降低成本的角度出發(fā)，往往選擇PLC來構(gòu)建控制系統(tǒng)。而鍋爐、汽機和發(fā)電機的控制系統(tǒng)，要求長期穩(wěn)定可靠地運行，信號中含有相當(dāng)比例的模擬量，從系統(tǒng)的性能出發(fā)，人們不得不選擇了昂貴的DCS。

另外，分析一下主廠房DCS和輔助車間控制系統(tǒng)的市場競爭情況，我們會發(fā)現(xiàn)一個有趣的現(xiàn)象。主廠房DCS的競爭往往在不同品牌的供應(yīng)商或代理商之間展開，競爭激烈，DCS的價格不斷下調(diào)。而輔助車間控制系統(tǒng)的競爭往往在同一品牌PLC的各個工程商之間進(jìn)行，門檻較低，競爭更加激烈，但是PLC的價格下調(diào)幅度卻并不如DCS明顯。主要原因是DCS的生產(chǎn)商直接參與競爭，在巨大的市場壓力下，不斷下調(diào)設(shè)備制造費用和工程實施費用。而PLC的生產(chǎn)商不直接參與競爭，各個工程商只能下調(diào)自身有限的工程費用，空間有限。從現(xiàn)在情況看來，DCS與高檔PLC的價格差距已不明顯，輔助車間仍然較多地采用PLC，是市場的慣性使然。

PLC和DCS產(chǎn)品市場可謂風(fēng)起云涌、競爭激烈?？v觀PLC市場群星璀璨：世界上有200多家公司生產(chǎn)400多個品種系列的PLC，應(yīng)用于電力、石油石化、冶金、材料、包裝、造紙、汽車和市政各個行業(yè)。從行業(yè)角度來看，國外廠商占山為王，有著屬于各自的勢力范圍。

DCS市場與PLC相差無幾，基本由國外業(yè)內(nèi)強者所把持，可喜的是一批本土廠商如Hollysys、Supcon、Xinhua等企業(yè)逐漸發(fā)展壯大。由于DCS技術(shù)含量高，很多對產(chǎn)品的需求都建立在項目的基礎(chǔ)上，這樣對DCS的需求也將是一個周期性較長的過程，因此DCS市場格短時間內(nèi)難有較大改變。當(dāng)然，由于行業(yè)發(fā)展速度的不規(guī)律性，側(cè)重行業(yè)不同的公司可能會因此而發(fā)生一些變化。

在今后的控制系統(tǒng)的發(fā)展中，我們將會看到DCS和PLC技術(shù)逐漸融合的面，這對它們各自的發(fā)展以及各行各業(yè)的發(fā)展都有種促進(jìn)的作用。

In the field of thermal automation, the main plant control system uses DCS almost without exception. PLCS are used in auxiliary workshops. The main reason is that the early DCS system is very expensive, people think that the operation of the auxiliary workshop can be interrupted, the reliability requirements are not very high, and the analog control requirements are less, from the point of view of reducing costs, often choose PLC to build the control system. The boiler, steam engine and generator control system, requiring long-term stable and reliable operation, the signal contains a considerable proportion of analog, from the performance of the system, people have to choose expensive DCS.
In addition, the analysis of the main plant DCS and auxiliary workshop control system market competition, we will find an interesting phenomenon. The competition of DCS in the main factory is often launched between suppliers or agents of different brands, and the competition is fierce, and the price of DCS is constantly lowered. The competition of auxiliary workshop control system is often carried out between the various engineers of the same brand PLC, the threshold is lower, the competition is more intense, but the price reduction of PLC is not as obvious as DCS. The main reason is that DCS manufacturers directly participate in competition, under huge market pressure, and constantly reduce equipment manufacturing costs and engineering implementation costs. PLC manufacturers do not directly participate in the competition, each engineer can only reduce their own limited project costs, limited space. From the current situation, the price gap between DCS and high-grade PLC is not obvious, and the auxiliary workshop still uses PLC more, which is caused by the inertia of the market.
PLC and DCS product market can be described as surging, fierce competition. Throughout the PLC market stars: there are more than 200 companies in the world to produce more than 400 varieties of PLC series, used in power, petroleum and petrochemical, metallurgy, materials, packaging, paper, automotive and municipal industries. From the perspective of the industry, foreign manufacturers are king of the mountain and have their own spheres of influence.
The DCS market is almost the same as PLC, basically dominated by foreign industry strong, fortunately, a number of local manufacturers such as Hollysys, Supcon, Xinhua and other enterprises have gradually developed and grown. Due to the high technical content of DCS, many of the demand for products are based on the project, so the demand for DCS will also be a cyclical longer process, so the DCS market is difficult to change in a short time. Of course, due to the irregular pace of industry development, there may be some changes in companies that focus on different industries.
In the future development of control systems, we will see the gradual integration of DCS and PLC technology, which has a role in promoting their respective development and the development of all walks of life.