什么是現(xiàn)場總線?
現(xiàn)場總線(Fieldbus)是20世紀(jì)80年代末、90年代初國際上發(fā)展形成的,用于現(xiàn)場總線技術(shù)過程自動(dòng)化、制造自動(dòng)化、樓宇自動(dòng)化等領(lǐng)域的現(xiàn)場智能設(shè)備互連通訊網(wǎng)絡(luò)。它作為工廠數(shù)字通信網(wǎng)絡(luò)的基礎(chǔ),溝通了生產(chǎn)過程現(xiàn)場及控制設(shè)備之間及其與更高控制管理層次之間的聯(lián)系。它不僅是一個(gè)基層網(wǎng)絡(luò),而且還是一種開放式、新型全分布控制系統(tǒng)。這項(xiàng)以智能傳感、控制、計(jì)算機(jī)、數(shù)字通訊等技術(shù)為主要內(nèi)容的綜合技術(shù),已經(jīng)受到世界范圍的關(guān)注,成為自動(dòng)化技術(shù)發(fā)展的熱點(diǎn),并將導(dǎo)致自動(dòng)化系統(tǒng)結(jié)構(gòu)與設(shè)備的深刻變革。現(xiàn)場總線設(shè)備的工作環(huán)境處于過程設(shè)備的底層,作為工廠設(shè)備級(jí)基礎(chǔ)通訊網(wǎng)絡(luò),要求具有協(xié)議簡單、容錯(cuò)能力強(qiáng)、安全性好、成本低的特點(diǎn):具有一定的時(shí)間確定性和較高的實(shí)時(shí)性要求,還具有網(wǎng)絡(luò)負(fù)載穩(wěn)定,多數(shù)為短幀傳送、信息交換頻繁等特點(diǎn)。由于上述特點(diǎn),現(xiàn)場總線系統(tǒng)從網(wǎng)絡(luò)結(jié)構(gòu)到通訊技術(shù),都具有不同上層高速數(shù)據(jù)通信網(wǎng)的特色。
目前國際上有40多種現(xiàn)場總線,但沒有任何一種現(xiàn)場總線能覆蓋所有的應(yīng)用面,按其傳輸數(shù)據(jù)的大小可分為3類:傳感器總線(sensorbus),屬于位傳輸;設(shè)備總線(devicebus),屬于字節(jié)傳輸;現(xiàn)場總線,屬于數(shù)據(jù)流傳輸。下面讓我一起去認(rèn)識(shí)主要的幾種總線。
PPC322BE
What is a fieldbus?
Fieldbus (Fieldbus) is the international development in the late 1980s and early 1990s, which is used for field intelligent equipment interconnection communication network in the field of fieldbus technology process automation, manufacturing automation, building automation and other fields. It is the basis of the digital communication network of the factory, which communicates the connection between the production process site and the control equipment and the higher control management level. It is not only a basic network, but also an open and new fully distributed control system. This integrated technology with intelligent sensing, control, computer, digital communication and other technologies as the main content has received worldwide attention, become a hot spot in the development of automation technology, and will lead to profound changes in the structure and equipment of automation systems. The working environment of fieldbus equipment is at the bottom of the process equipment. As a basic communication network at the factory equipment level, it requires simple protocol, strong fault tolerance, good security and low cost. It has certain time certainty and high real-time requirements, and it also has the characteristics of stable network load, mostly short frame transmission and frequent information exchange. Because of the above characteristics, the fieldbus system has the characteristics of different high speed data communication networks from the network structure to the communication technology.
At present, there are more than 40 kinds of fieldbuses in the world, but no fieldbus can cover all applications, according to the size of its transmission data can be divided into three categories: sensorbus (sensorbus), which belongs to bit transmission; Device bus (devicebus), which belongs to byte transmission; Fieldbus, which belongs to data stream transmission. Let me go to know the main bus.