基于上述幾點(diǎn)的建議,我們討論了工業(yè)以太網(wǎng)交換機(jī)的應(yīng)用特性,以及在不同場(chǎng)合下的應(yīng)用的設(shè)備類型。由于各種品牌的工業(yè)以太網(wǎng)交換機(jī)在設(shè)備命名規(guī)則上差異較大,因此在選購(gòu)前最好向供應(yīng)商進(jìn)行咨詢,以選擇適合的產(chǎn)品。交換機(jī)路由器功能比較:
1.工作層次不同
交換機(jī)工作在OSI的第二層,而路由器工作在OSI的第三層。由于交換機(jī)工作在OSI的第二層(數(shù)據(jù)鏈路層),所以它的工作原理比較簡(jiǎn)單,而路由器工作在OSI的第三層(網(wǎng)絡(luò)層),可以得到更多的協(xié)議信息,路由器可以做出更加智能的轉(zhuǎn)發(fā)決策。
2.數(shù)據(jù)轉(zhuǎn)發(fā)所依據(jù)的對(duì)象不同
交換機(jī)是利用MAC地址來(lái)確定轉(zhuǎn)發(fā)數(shù)據(jù)的目的地址。而路由器則是利用IP地址來(lái)確定數(shù)據(jù)轉(zhuǎn)發(fā)的地址。IP地址是在軟件中設(shè)置的,描述的是設(shè)備所在的網(wǎng)絡(luò),這些第三層的地址也稱為協(xié)議地址或者網(wǎng)絡(luò)地址。MAC地址通常是硬件自帶的,由網(wǎng)卡產(chǎn)商來(lái)分配的,并且已經(jīng)固化到了網(wǎng)卡中。而IP地址則通常由網(wǎng)絡(luò)管理員或系統(tǒng)自動(dòng)分配。
工業(yè)交換機(jī)一般用于LAN-WAN的連接,路由器用于WAN-WAN之間的連接,可以解決不同網(wǎng)段之間轉(zhuǎn)發(fā)。
3.廣播域的劃分
交換機(jī)只能分割沖突域,不能分割廣播域;而路由器可以分割廣播域
由交換機(jī)連接的網(wǎng)段屬于同一個(gè)廣播域,廣播包會(huì)在交換機(jī)連接的所有網(wǎng)段上傳播,在某些情況下會(huì)導(dǎo)致通信擁擠和安全漏洞。連接到路由器上的網(wǎng)段會(huì)被分配成不同的廣播域,廣播數(shù)據(jù)不會(huì)穿過(guò)路由器。雖然第三層以上交換機(jī)具有VLAN功能,也可以分割廣播域,但各子廣播域之間是不能通信交流的,它們之間的交流仍然需要路由器。
4.安全性的區(qū)別
路由器提供了防火墻、訪問(wèn)限制等服務(wù)可以實(shí)現(xiàn)數(shù)據(jù)的過(guò)濾。路由器僅僅轉(zhuǎn)發(fā)特定地址的數(shù)據(jù)包,不轉(zhuǎn)發(fā)不支持路由協(xié)議的數(shù)據(jù)包傳送和未知目標(biāo)網(wǎng)絡(luò)數(shù)據(jù)包的傳送,從而可以防止廣播風(fēng)暴。
5.硬件的區(qū)別
路由器的LAN口一般只有4個(gè)以下,而交換機(jī)的LAN口數(shù)量在4-48口不等。工業(yè)路由器有WAN口并且支持手機(jī)卡上網(wǎng),而交換機(jī)不行。路由器帶wifi芯片,而交換機(jī)沒(méi)有。
Therefore, compared with the traditional water tank wire drawing machine, it has less swing rod link of direct tension detection. HMI is used for data setting and monitoring of operating parameters.
3、 PLC control principle the core control of PLC is the difference between wire drawing speed and take-up speed, that is, the constant slip, which indirectly ensures the constant take-up tension. It can be seen from the above figure that the linear speed signal detected by the guide wheel is input to x0 of PLC. The rotation of the guide wheel belongs to a free state, and the friction coefficient is very small, so there is no slip between the wire and the guide wheel. The linear speed detected by the guide wheel reflects the real linear speed and take-up speed of the material. The constant speed wheel through X1 detection reflects the wire drawing speed, but the wire drawing must have slip, which must be faster than the linear speed of take-up, otherwise the wire coming out will be very tight and easy to cause wire breakage; On the contrary, if the linear speed of the constant speed wheel is too fast and the slip is too