應用PLC技(ji)術實現對(dui)機械(xie)手的控制，其任務(wu)是(shi)將工件(jian)從傳送帶A搬運到傳送帶B。采用移位(wei)指令設計順控程序。

機械(xie)手的(de)動(dong)作示意圖如圖1所示，它是一個(ge)能夠(gou)產生水平/垂直(zhi)位移的(de)機械(xie)設備，用(yong)來將工件由左工作臺搬運到右工作臺。

圖 1

1、工藝過程與控制要求(qiu)

機械(xie)手(shou)(shou)的(de)全部動(dong)作(zuo)由(you)(you)(you)氣(qi)缸(gang)驅動(dong)，而氣(qi)缸(gang)又由(you)(you)(you)相(xiang)應(ying)的(de)電(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)控(kong)制(zhi)。其(qi)中(zhong)，上升/下(xia)(xia)降(jiang)和左(zuo)轉(zhuan)(zhuan)(zhuan)(zhuan)/右(you)轉(zhuan)(zhuan)(zhuan)(zhuan)分(fen)別由(you)(you)(you)雙線圈兩位電(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)控(kong)制(zhi)。例如：當(dang)(dang)(dang)(dang)下(xia)(xia)降(jiang)電(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)通電(dian)(dian)時，機械(xie)手(shou)(shou)下(xia)(xia)降(jiang)；當(dang)(dang)(dang)(dang)下(xia)(xia)降(jiang)電(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)斷電(dian)(dian)時，機械(xie)手(shou)(shou)下(xia)(xia)降(jiang)停止(zhi)。只有當(dang)(dang)(dang)(dang)上升電(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)通電(dian)(dian)時，機械(xie)手(shou)(shou)才上升；當(dang)(dang)(dang)(dang)上升電(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)斷電(dian)(dian)時，機械(xie)手(shou)(shou)上升停止(zhi)。同樣，左(zuo)轉(zhuan)(zhuan)(zhuan)(zhuan)/右(you)轉(zhuan)(zhuan)(zhuan)(zhuan)分(fen)別由(you)(you)(you)左(zuo)轉(zhuan)(zhuan)(zhuan)(zhuan)電(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)和右(you)轉(zhuan)(zhuan)(zhuan)(zhuan)電(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)控(kong)制(zhi)。機械(xie)手(shou)(shou)的(de)放(fang)松(song)/夾緊(jin)由(you)(you)(you)一個單線圈兩位電(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(稱為(wei)夾緊(jin)電(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa))來控(kong)制(zhi)氣(qi)缸(gang)的(de)運動(dong)。當(dang)(dang)(dang)(dang)該線圈通電(dian)(dian)時，機械(xie)手(shou)(shou)夾緊(jin)；當(dang)(dang)(dang)(dang)該線圈斷電(dian)(dian)時，機械(xie)手(shou)(shou)放(fang)松(song)。

當機械手右移到位并準備下降時，為了確保安全，必須在右工作臺無工件時才允許機械手下降。也就是說，若上一次搬運到右工作臺上的工件尚未搬走時，機械手應自動停止下降，用光電開關I0.5進行無工件檢測。

機(ji)(ji)械(xie)手(shou)(shou)(shou)的(de)動作(zuo)(zuo)過程如圖(tu)2所示(shi)。從原(yuan)點開(kai)始，按下(xia)(xia)啟(qi)動按鈕，下(xia)(xia)降(jiang)(jiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)通(tong)(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，機(ji)(ji)械(xie)手(shou)(shou)(shou)下(xia)(xia)降(jiang)(jiang)。下(xia)(xia)降(jiang)(jiang)到(dao)(dao)(dao)底時(shi)(shi)(shi)(shi)，碰(peng)到(dao)(dao)(dao)下(xia)(xia)限位(wei)(wei)開(kai)關(guan)，下(xia)(xia)降(jiang)(jiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)斷(duan)(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，下(xia)(xia)降(jiang)(jiang)停(ting)止(zhi)；同時(shi)(shi)(shi)(shi)接(jie)通(tong)(tong)(tong)夾(jia)(jia)緊(jin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)，機(ji)(ji)械(xie)手(shou)(shou)(shou)夾(jia)(jia)緊(jin)。夾(jia)(jia)緊(jin)后，上(shang)升(sheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)通(tong)(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，機(ji)(ji)械(xie)手(shou)(shou)(shou)上(shang)升(sheng)。上(shang)升(sheng)到(dao)(dao)(dao)頂時(shi)(shi)(shi)(shi)，碰(peng)到(dao)(dao)(dao)上(shang)限位(wei)(wei)開(kai)關(guan)，上(shang)升(sheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)斷(duan)(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，上(shang)升(sheng)停(ting)止(zhi)；同時(shi)(shi)(shi)(shi)接(jie)通(tong)(tong)(tong)右(you)移(yi)(yi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)，機(ji)(ji)械(xie)手(shou)(shou)(shou)右(you)移(yi)(yi)。右(you)移(yi)(yi)到(dao)(dao)(dao)位(wei)(wei)時(shi)(shi)(shi)(shi)，碰(peng)到(dao)(dao)(dao)右(you)限位(wei)(wei)開(kai)關(guan)，右(you)移(yi)(yi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)斷(duan)(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，右(you)移(yi)(yi)停(ting)止(zhi)。若此時(shi)(shi)(shi)(shi)右(you)工(gong)作(zuo)(zuo)臺(tai)上(shang)無工(gong)件，則光電(dian)(dian)(dian)(dian)(dian)(dian)(dian)開(kai)關(guan)接(jie)通(tong)(tong)(tong)，下(xia)(xia)降(jiang)(jiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)通(tong)(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，機(ji)(ji)械(xie)手(shou)(shou)(shou)下(xia)(xia)降(jiang)(jiang)。下(xia)(xia)降(jiang)(jiang)到(dao)(dao)(dao)底時(shi)(shi)(shi)(shi)，碰(peng)到(dao)(dao)(dao)下(xia)(xia)限位(wei)(wei)開(kai)關(guan)，下(xia)(xia)降(jiang)(jiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)斷(duan)(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，下(xia)(xia)降(jiang)(jiang)停(ting)止(zhi)； 同時(shi)(shi)(shi)(shi)夾(jia)(jia)緊(jin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)斷(duan)(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，機(ji)(ji)械(xie)手(shou)(shou)(shou)放(fang)松(song)。放(fang)松(song)后，上(shang)升(sheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)通(tong)(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，機(ji)(ji)械(xie)手(shou)(shou)(shou)上(shang)升(sheng)。上(shang)升(sheng)到(dao)(dao)(dao)頂時(shi)(shi)(shi)(shi)， 碰(peng)到(dao)(dao)(dao)上(shang)限位(wei)(wei)開(kai)關(guan)，上(shang)升(sheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)斷(duan)(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，上(shang)升(sheng)停(ting)止(zhi)；同時(shi)(shi)(shi)(shi)接(jie)通(tong)(tong)(tong)左(zuo)移(yi)(yi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)，機(ji)(ji)械(xie)手(shou)(shou)(shou)左(zuo)移(yi)(yi)。左(zuo)移(yi)(yi)到(dao)(dao)(dao)原(yuan)點時(shi)(shi)(shi)(shi)，碰(peng)到(dao)(dao)(dao)左(zuo)限位(wei)(wei)開(kai)關(guan)，左(zuo)移(yi)(yi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)斷(duan)(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，左(zuo)移(yi)(yi)停(ting)止(zhi)。至(zhi)此，機(ji)(ji)械(xie)手(shou)(shou)(shou)經(jing)過八步動作(zuo)(zuo)完(wan)成了一(yi)個周期的(de)動作(zuo)(zuo)。

圖(tu) 2

機械手的(de)操(cao)作(zuo)方(fang)式分為(wei)手動操(cao)作(zuo)方(fang)式和自動操(cao)作(zuo)方(fang)式。自動操(cao)作(zuo)方(fang)式又(you)分為(wei)步進、單(dan)周(zhou)期和連續操(cao)作(zuo)三(san)種方(fang)式。

（1）手(shou)(shou)動(dong)(dong)操作(zuo)：就是用按(an)鈕(niu)(niu)操作(zuo)對機(ji)械手(shou)(shou)的每(mei)步運動(dong)(dong)單獨進行控制。例(li)如，當選(xuan)擇(ze)上/下(xia)(xia)運動(dong)(dong)時，按(an)下(xia)(xia)啟動(dong)(dong)按(an)鈕(niu)(niu)，機(ji)械手(shou)(shou)下(xia)(xia)降；按(an)下(xia)(xia)停(ting)(ting)(ting)止(zhi)按(an)鈕(niu)(niu)，機(ji)械手(shou)(shou)上升。當選(xuan)擇(ze)左/右運動(dong)(dong)時，按(an)下(xia)(xia)啟動(dong)(dong)按(an)鈕(niu)(niu)，機(ji)械手(shou)(shou)右移；按(an)下(xia)(xia)停(ting)(ting)(ting)止(zhi)按(an)鈕(niu)(niu)，機(ji)械手(shou)(shou)左移。當選(xuan)擇(ze)夾(jia)緊(jin)/放松運動(dong)(dong)時，按(an)下(xia)(xia)啟動(dong)(dong)按(an)鈕(niu)(niu)，機(ji)械手(shou)(shou)夾(jia)緊(jin)；按(an)下(xia)(xia)停(ting)(ting)(ting)止(zhi)按(an)鈕(niu)(niu)，機(ji)械手(shou)(shou)放松。

（2）步(bu)(bu)進操作(zuo)：每(mei)按(an)一(yi)(yi)次(ci)啟動(dong)按(an)鈕，機(ji)械手完成一(yi)(yi)步(bu)(bu)動(dong)作(zuo)后自(zi)動(dong)停止。

（3）單周期(qi)操作：機械(xie)(xie)手(shou)(shou)從原點開始，按(an)一下啟動按(an)鈕，機械(xie)(xie)手(shou)(shou)自動完(wan)成(cheng)一個(ge)周期(qi)的動作后停(ting)止。

（4）連續(xu)操(cao)作(zuo)：機(ji)械手從原(yuan)點(dian)(dian)開始，按(an)一下(xia)啟(qi)動按(an)鈕，機(ji)械手的動作(zuo)將自動地(di)、連續(xu)不(bu)斷地(di)周(zhou)期性循環。在工(gong)作(zuo)中(zhong)若按(an)下(xia)停止按(an)鈕，則機(ji)械手將繼續(xu)完成一個周(zhou)期的動作(zuo)后，回到原(yuan)點(dian)(dian)自動停止。

2、操作面板布(bu)置

圖3位操作面板布置圖。

接通I0.7是單操作方式。按加載選擇開關的位置，用啟動/停止按鈕選擇加載操作，當加載選擇開關打到“左右”位置時，按下啟動按鈕，機械手右行;若按下停止按鈕，機械手左行。用上述操作可使機械手停在原點。

接通I1.0是步進方式。機械手在原點時，按下啟動按鈕，向前操作一步;每按啟動按鈕一次，操作一步。接通I1.1是單周期操作方式。機械手在原點時，按下啟動按鈕，自動操作一個周期。接通I1.2是連續操作方式。機械手在原點時，按下啟動按鈕，連續執行自動周期操作，當按下停止按鈕，機械手完成此周期動作后自動回到原點并不再動作。

圖(tu) 3

3、輸(shu)(shu)入/輸(shu)(shu)出端子地址分配機械手控制系統所采用的PLC是德國西門子公司生產的S7-200CPU214，圖4是S7-200 CPU214輸入/輸出端子地址分配圖。該機械手控制系統共使用了14個輸入量，6個輸出量。

圖 4

4、整體(ti)程序(xu)結構(gou)

機械手的整體程序結構如圖5所示。若選擇單操作工作方式，I0.7斷開,接著執行單操作程序。(單操作程序可以獨立于自動操作程序，可另行設計)。

在單周期(qi)工(gong)作方(fang)式和連續操(cao)作方(fang)式下(xia)，可執(zhi)(zhi)行自(zi)動操(cao)作程序(xu)(xu)(xu)。在步進(jin)工(gong)作方(fang)式，執(zhi)(zhi)行步進(jin)操(cao)作程序(xu)(xu)(xu)，按一下(xia)啟動按鈕執(zhi)(zhi)行一個動作，并(bing)按規(gui)定順(shun)序(xu)(xu)(xu)進(jin)行。

在需要自動操作方式時，中間繼電器M1.0接通。步進工作方式、單操作工作方式和自動操作方式，都用同樣的輸出繼電器。