LWN1902-6脈沖輸入通道模塊

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型號：LWN1902-6
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LWN1902-6脈沖輸入通道模塊

在本系統(tǒng)中每個就地操作站都配有一臺上位監(jiān)控機(jī)，這臺上位機(jī)不僅能操作本地站，在一定的授權(quán)下還能對其他站進(jìn)行監(jiān)視和控制。中控室配有二臺上位監(jiān)控機(jī)，他們能同時控制所有四個就地控制站，向其發(fā)送命令。這六個上位監(jiān)控機(jī)之間的關(guān)系是互為功能備用的，這就是說這六個監(jiān)控站中只要有一個發(fā)生故障，另外的五個監(jiān)控站通過一定的授權(quán)就能代替該站的工作。系統(tǒng)中所有設(shè)備的電源均由UPS提供，每個儀表的電源都由開關(guān)型端子控制，能獨(dú)立開關(guān)。保證了系統(tǒng)安全性，和調(diào)試的方便性。在前幾年的住宅建設(shè)中,鋼筋混凝土預(yù)制板是構(gòu)成磚混結(jié)構(gòu)房屋的重要構(gòu)件,但是,其本身由于在構(gòu)造上存在著一些致命的缺陷,即整體性及抗震性差,因此,在近幾年的住宅建設(shè)中它逐步被鋼筋混凝土現(xiàn)澆板所替代,但是,隨著鋼筋混凝土現(xiàn)澆板在房屋建設(shè)中的大量推廣與應(yīng)用,它的裂縫問題也越來越引起人們的注意。二.鋼筋混凝土現(xiàn)澆板裂縫原因的分析筆者通過這些年對所接觸到的鋼筋混凝土現(xiàn)澆板裂縫問題的調(diào)查與分析,認(rèn)為它主要是由以下幾個方面的原因造成的:1)混凝土的收縮,2)混凝土的原材料質(zhì)量,3)施工的質(zhì)量,4)荷載的作用, 5)設(shè)備專業(yè)的影響,6)地基的不均勻沉降等.有時候,它的裂縫往往是由幾個方面的原因共同作用所致。下面,筆者對這幾個方面的原因逐一作簡單的分析。 1.混凝土的收縮眾所周知,混凝土引起收縮的原因,在硬化初期主要是由于水泥的水化作用,形成一種新的水泥結(jié)晶體,這種結(jié)晶體化合物較原材料體積小,因而引起混凝土體積的收縮,即所謂的凝縮,后期主要是混凝土內(nèi)自由水蒸發(fā)而引起的干縮.而且,如果混凝土處在一個溫差變化較大的環(huán)境下,將會使其收縮更為加劇。目前,以我市的住宅建設(shè)為例,鋼筋混凝土現(xiàn)澆板中的裂縫,大部分是由于混凝土的收縮原因引起的.由于混凝土自身在硬化過程中存在凝縮和干縮,加上我市在一年中的氣溫相差較大,夏季高氣溫可超過35OC,而到冬季低氣溫達(dá)-10oC(參考有關(guān)資料),相差45o C,而混凝土的膨脹系數(shù)為10-5/0C,所以,經(jīng)過一年的夏冬交替,混凝土的溫差應(yīng)變可達(dá)400uε以上,考慮到柱.墻對現(xiàn)澆板的約束系數(shù)為0.25---0.35,混凝土的結(jié)構(gòu)溫差應(yīng)變約為60---110uε,因此,鋼筋混凝土現(xiàn)澆板在這種情況下,很容易出現(xiàn)裂縫。 2.混凝土原材料的質(zhì)量在住宅建設(shè)中,也有一部分鋼筋混凝土現(xiàn)澆板出現(xiàn)的裂縫,是由于用來制作現(xiàn)澆板的原材料質(zhì)量不合格所造成的.如水泥凝結(jié)或膨脹不正常,則產(chǎn)生既短又不規(guī)則的裂縫,這種裂縫多產(chǎn)生在混凝土硬化的早期;如果骨料中含泥量過多,則隨著混凝土的干燥,會產(chǎn)生不規(guī)則的網(wǎng)狀裂縫;有時堿----骨料反應(yīng),也會引起裂縫. 3.施工的缺陷在住宅建設(shè)中,有相當(dāng)一部分的鋼筋混凝土現(xiàn)澆板出現(xiàn)裂縫,是由于施工方面的原因造成的,這些原因包括以下幾個方面:混凝土的強(qiáng)度等級達(dá)不到設(shè)計要求,現(xiàn)澆板的厚度不夠,鋼筋的放置不到位,配筋量的不足等均會造成現(xiàn)澆板的撓度過大,從而引起它在受彎抗拉處產(chǎn)生裂縫;剛澆筑的混凝土板也會因模板支撐下沉,使樓板撓度加大,拆模后也會出現(xiàn)裂縫;特別是對于陽臺.雨蓬.挑檐等懸臂構(gòu)件,往往由于工人在澆灌混凝土過程中,將板上的負(fù)彎矩鋼筋踩倒,使構(gòu)件不能承受負(fù)彎矩從而引起裂縫,嚴(yán)重的甚至于引起這些構(gòu)件斷裂。 4.荷載的作用在住宅建設(shè)中,也有少部分鋼筋混凝土現(xiàn)澆板的裂縫,是由于荷載作用方面的原因引起的.由于設(shè)計人員在進(jìn)行現(xiàn)澆板的配筋計算過程中,通常只是根據(jù)其承載能力來確定配筋量的,而往往忽略了對板在正常使用階段由其承受的荷載而引起的撓度及裂縫寬度的驗(yàn)算,由此而引起裂縫的產(chǎn)生,這些裂縫有時也會超過規(guī)范的大允許值,這也應(yīng)當(dāng)引起足夠的重視. 5.設(shè)備專業(yè)的影響在住宅建設(shè)中,鋼筋混凝土現(xiàn)澆板的裂縫也有一部分是受設(shè)備專業(yè)的影響引起的.目前,在樓房的設(shè)計中,設(shè)備專業(yè)特別是電氣專業(yè),大多將照明.有線電視.通訊等所需的管線直接敷設(shè)于現(xiàn)澆板中,而且有時集中于某一處現(xiàn)澆板中的管線多達(dá)7----8根,并且這些管線的直徑多為2---3CM,由此就會使該處的現(xiàn)澆板厚度大大削弱,從而引起現(xiàn)澆板在該處開裂. 6.地基的不均勻沉降在住宅建設(shè)中,也有相當(dāng)一部分的鋼筋混凝土現(xiàn)澆板的裂縫,是由于地基不均勻沉降的原因而造成的.以我市為例，我市的建筑場地約80%為軟土場地,其層理構(gòu)造一般為:表面1--1.5米為粘土,第二層為淤泥或淤泥質(zhì)土.厚度為6--25米,其下為承載力較高的粘土層,故我市大部分四層以上的住宅均采用樁基,但也有相當(dāng)一部分低于四層的住宅樓采用擴(kuò)展基礎(chǔ),在我市的這種地質(zhì)情況下,如果采用這種基礎(chǔ)形式,則對于那些相對較長的條式樓來說,要想保正它們沉降均勻是相當(dāng)困難的，因此,在這種情況下,有時也會由于基礎(chǔ)的不均勻沉降,而引起樓房的拉裂和鋼筋混凝土現(xiàn)澆板的開裂.In this system, each local operation station is equipped with an upper monitoring computer, which can not only operate the local station, but also monitor and control other stations under certain authorization. The central control room is equipped with two upper monitoring computers, which can simultaneously control all four local control stations and send commands to them. The relationship between the six upper monitoring computers is functional backup, which means that as long as one of the six monitoring stations fails, the other five monitoring stations can replace the work of the station with certain authorization. The power supply of all equipment in the system is provided by UPS. The power supply of each instrument is controlled by switch type terminals and can be switched independently. The system security and debugging convenience are guaranteed. In previous years' residential construction, the reinforced concrete precast slab is an important component of the brick concrete structure house. However, due to some fatal defects in its structure, namely poor integrity and seismic resistance, it has been gradually replaced by the steel reinforced concrete cast-in-situ slab in recent years' residential construction. However, with the massive promotion and application of the reinforced concrete cast-in-situ slab in housing construction, Its crack problem has also attracted more and more attention. II Analysis of the causes of cracks in reinforced concrete cast-in-place slabs The author, through his investigation and analysis of the cracks in reinforced concrete cast-in-place slabs he has been exposed to over the years, believes that they are mainly caused by the following factors: 1) shrinkage of concrete, 2) quality of concrete raw materials, 3) quality of construction, 4) role of load, 5) influence of equipment discipline, 6) uneven settlement of foundation, etc Sometimes, its cracks are often caused by several reasons. Next, the author makes a simple analysis on the reasons of these aspects one by one. 1. The shrinkage of concrete is well known. The reason for the shrinkage of concrete is mainly due to the hydration of cement in the early hardening stage, which forms a new cement crystal. This crystal compound is smaller than the volume of raw materials, thus causing the shrinkage of concrete volume, which is called condensation. In the late hardening stage, it is mainly caused by the evaporation of free water in the concrete Moreover, if the concrete is in an environment where the temperature difference changes greatly, its shrinkage will be more intensified. At present, taking the residential construction in our city as an example, most of the cracks in the reinforced concrete cast-in-situ slab are caused by the shrinkage of concrete As the concrete itself has condensation and drying shrinkage during the hardening process, and the temperature difference in our city is large, the highest temperature in summer can exceed 35OC, and the lowest temperature in winter can reach - 10oC (refer to relevant data), with a difference of 45oC, while the expansion coefficient of concrete is 10-5/0C, so the temperature difference strain of concrete can reach 400u after the alternation of summer and winter in a year ε Above, considering that the restraint coefficient of column and wall to cast-in-place slab is 0.25 -- -0.35, and the temperature difference strain of concrete structure is about 60 -- 110u ε, Therefore, the reinforced concrete cast-in-situ slab is easy to crack in this case. 2. The quality of concrete raw materials In residential construction, there are also cracks in some reinforced concrete cast-in-place slabs, which are caused by unqualified raw materials used to make cast-in-place slabs If the cement setting or expansion is abnormal, short and irregular cracks will be generated, which are mostly generated in the early stage of concrete hardening; If the aggregate contains too much mud, irregular network cracks will occur with the drying of concrete; Sometimes alkali aggregate reaction will also cause cracks 3. Construction defects In residential construction, a considerable part of the cast-in-place reinforced concrete slabs have cracks due to construction reasons, including the following aspects: the strength grade of the concrete does not meet the design requirements, the thickness of the cast-in-place slab is not enough, the reinforcement is not placed in place, and the amount of reinforcement is insufficient, which will cause the cast-in-place slab to deflect too much, resulting in cracks at the bending and tension; The newly poured concrete slab will also sink due to the support of the formwork, which will increase the deflection of the floor slab, and cracks will also appear after the removal of the formwork; Especially for balconies and awnings Cantilever components, such as overhanging eaves, often cause cracks because workers step down the negative moment reinforcement on the slab during concrete pouring, which makes the component unable to bear the negative moment, and even cause these components to break seriously. 4. In residential construction, there are also a few cracks in cast-in-place reinforced concrete slabs due to the load effect During the reinforcement calculation of cast-in-place slabs, designers usually determine the reinforcement amount only according to its bearing capacity, and often neglect the checking calculation of the deflection and crack width caused by the load borne by the slabs in the normal use stage, which leads to cracks. These cracks sometimes exceed the maximum allowable value of the specification, which should also be paid enough attention 5. The influence of equipment profession In residential construction, the cracks of reinforced concrete cast-in-situ slab are also partly caused by the influence of equipment profession. At present, in the design of buildings, the equipment profession, especially the electrical profession, mostly lights and cable TV The pipelines required for communication are directly laid in the cast-in-place slab, and sometimes there are as many as 7-8 pipelines concentrated in a certain cast-in-place slab, and the diameter of these pipelines is mostly 2-3CM, which will greatly weaken the thickness of the cast-in-place slab at this location, thus causing the cast-in-place slab to crack at this location 6. Uneven settlement of the foundation In residential construction, there are also quite a number of cracks in the cast-in-place reinforced concrete slabs, which are caused by the uneven settlement of the foundation. Taking our city as an example, about 80% of the construction sites in our city are soft soil sites, and the bedding structure is generally: the surface is 1 to 1.5 meters of clay, and the second layer is silt or muddy soil The thickness is 6 to 25 meters, and the clay layer with high bearing capacity is below it. Therefore, most of the residential buildings with more than four floors in our city use pile foundations, but a considerable number of residential buildings with less than four floors use extended foundations. Under this geological situation in our city, if this foundation form is adopted, it is quite difficult to ensure the settlement of relatively long strip buildings is uniform. Therefore, in this case, Sometimes, the uneven settlement of the foundation will cause the tension cracking of the building and the cracking of the cast-in-place reinforced concrete slab

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