如何觀看工控主板的做工質量?下面一(yi)起來學習下吧。

　　一、布線(xian)設計

　　工(gong)控(kong)主(zhu)板(ban)(ban)(ban)(ban)上的(de)(de)(de)布線(xian)(xian)(xian)(xian)(xian)設(she)計(ji)是(shi)一門比較專(zhuan)業的(de)(de)(de)學問(wen)，它要(yao)視不(bu)(bu)同的(de)(de)(de)線(xian)(xian)(xian)(xian)(xian)路(lu)特性進行(xing)(xing)不(bu)(bu)同的(de)(de)(de)設(she)計(ji)處理方式(shi)。工(gong)控(kong)主(zhu)板(ban)(ban)(ban)(ban)上采(cai)用(yong)的(de)(de)(de)"蛇(she)(she)行(xing)(xing)布線(xian)(xian)(xian)(xian)(xian)"就(jiu)很(hen)有講究，有些(xie)人認為蛇(she)(she)行(xing)(xing)布線(xian)(xian)(xian)(xian)(xian)越多(duo)就(jiu)說明有更高的(de)(de)(de)設(she)計(ji)水(shui)平，這(zhe)種觀點是(shi)錯(cuo)誤的(de)(de)(de)。采(cai)用(yong)蛇(she)(she)行(xing)(xing)布線(xian)(xian)(xian)(xian)(xian)的(de)(de)(de)原(yuan)因有兩(liang)個(ge)：一個(ge)是(shi)為了(le)保(bao)證(zheng)布線(xian)(xian)(xian)(xian)(xian)線(xian)(xian)(xian)(xian)(xian)路(lu)的(de)(de)(de)等長，因為像(xiang)CPU到北(bei)橋芯(xin)片的(de)(de)(de)時(shi)鐘線(xian)(xian)(xian)(xian)(xian)，它不(bu)(bu)同于普通電器(qi)上的(de)(de)(de)線(xian)(xian)(xian)(xian)(xian)路(lu)，在這(zhe)些(xie)線(xian)(xian)(xian)(xian)(xian)路(lu)上以(yi)(yi)100MHz左右的(de)(de)(de)頻率高速(su)運行(xing)(xing)的(de)(de)(de)信號(hao)對(dui)線(xian)(xian)(xian)(xian)(xian)路(lu)的(de)(de)(de)長度(du)十分(fen)的(de)(de)(de)敏感(gan),不(bu)(bu)等長的(de)(de)(de)時(shi)鐘布線(xian)(xian)(xian)(xian)(xian)路(lu)會引起(qi)信號(hao)的(de)(de)(de)不(bu)(bu)同步(bu)進而造成系統不(bu)(bu)穩(wen),這(zhe)樣某(mou)些(xie)線(xian)(xian)(xian)(xian)(xian)路(lu)需(xu)要(yao)以(yi)(yi)彎(wan)曲的(de)(de)(de)方式(shi)走線(xian)(xian)(xian)(xian)(xian),以(yi)(yi)調節長度(du);另一個(ge)使(shi)(shi)用(yong)蛇(she)(she)行(xing)(xing)布線(xian)(xian)(xian)(xian)(xian)的(de)(de)(de)常見(jian)原(yuan)因是(shi)為了(le)盡(jin)(jin)可能(neng)(neng)減少電磁輻射(she)(EMI)對(dui)主(zhu)板(ban)(ban)(ban)(ban)其余部(bu)件和(he)人體(ti)的(de)(de)(de)影(ying)響，因為高速(su)而單調的(de)(de)(de)數字信號(hao)會大(da)大(da)地干擾主(zhu)板(ban)(ban)(ban)(ban)上模擬器(qi)件的(de)(de)(de)工(gong)作，如AC''97芯(xin)片或(huo)板(ban)(ban)(ban)(ban)載的(de)(de)(de)軟貓等。平常抑(yi)制EMI的(de)(de)(de)一種簡便(bian)方法就(jiu)是(shi)通過(guo)設(she)計(ji)蛇(she)(she)形布線(xian)(xian)(xian)(xian)(xian)，來(lai)盡(jin)(jin)可能(neng)(neng)多(duo)吸收消(xiao)化輻射(she)。采(cai)用(yong)蛇(she)(she)行(xing)(xing)布線(xian)(xian)(xian)(xian)(xian)有了(le)上面(mian)這(zhe)些(xie)好(hao)處，并不(bu)(bu)是(shi)說在工(gong)控(kong)主(zhu)板(ban)(ban)(ban)(ban)布線(xian)(xian)(xian)(xian)(xian)設(she)計(ji)的(de)(de)(de)時(shi)候使(shi)(shi)用(yong)蛇(she)(she)行(xing)(xing)布線(xian)(xian)(xian)(xian)(xian)越多(duo)越好(hao)，因為過(guo)多(duo)過(guo)密的(de)(de)(de)主(zhu)板(ban)(ban)(ban)(ban)布線(xian)(xian)(xian)(xian)(xian)會造成工(gong)控(kong)主(zhu)板(ban)(ban)(ban)(ban)布局的(de)(de)(de)疏密不(bu)(bu)均，會對(dui)工(gong)控(kong)主(zhu)板(ban)(ban)(ban)(ban)的(de)(de)(de)質量有一定的(de)(de)(de)影(ying)響。好(hao)的(de)(de)(de)布線(xian)(xian)(xian)(xian)(xian)應使(shi)(shi)工(gong)控(kong)主(zhu)板(ban)(ban)(ban)(ban)上各部(bu)分(fen)線(xian)(xian)(xian)(xian)(xian)路(lu)密度(du)差別不(bu)(bu)大(da)，并且要(yao)盡(jin)(jin)可能(neng)(neng)均勻(yun)分(fen)布否則很(hen)容易(yi)造成工(gong)控(kong)主(zhu)板(ban)(ban)(ban)(ban)的(de)(de)(de)不(bu)(bu)穩(wen)定。

　　二、做工(gong)用料

　　1、PCB(印刷電路板(ban))的做工

　　質量有保證的(de)PC板(ban)色彩基本保持(chi)一(yi)(yi)致，光潔度好(hao)(hao)，看(kan)起來(lai)油(you)光發亮的(de)一(yi)(yi)般質量就比(bi)較好(hao)(hao)。PCB板(ban)層(ceng)數(shu)一(yi)(yi)般的(de)標準是(shi)4、6層(ceng)板(ban)，當然(ran)6層(ceng)板(ban)質量要好(hao)(hao)很多。

　　2、SMT(表面(mian)貼裝)元器件的做工

　　主要通過(guo)觀察某些元器(qi)(qi)件貼(tie)裝(zhuang)精度來(lai)判(pan)定(ding)主板(ban)的(de)生(sheng)產工藝(yi)是否精良，標準(zhun)的(de)元器(qi)(qi)件貼(tie)裝(zhuang)定(ding)位準(zhun)確，沒有偏移。

　　3、工控(kong)主(zhu)板用料

　　名牌大廠所生(sheng)產(chan)的工控主板用(yong)料(liao)，像CPU插(cha)座(zuo)、擴展槽和(he)插(cha)槽等都采用(yong)名廠的插(cha)接界面元(yuan)器件，主板的性能(neng)也就不用(yong)多說了(le)。