PLC通(tong)常通(tong)過輸(shu)(shu)出(chu)脈(mo)沖(chong)(chong)(chong)來(lai)進行伺服控制(zhi)。從(cong)硬(ying)件上看，具有(you)(you)脈(mo)沖(chong)(chong)(chong)輸(shu)(shu)出(chu)的(de)通(tong)道個數(shu)。小型PLC提供的(de)脈(mo)沖(chong)(chong)(chong)輸(shu)(shu)出(chu)通(tong)道<=4路。從(cong)指令上看，輸(shu)(shu)出(chu)脈(mo)沖(chong)(chong)(chong)有(you)(you)獨(du)立輸(shu)(shu)出(chu)型，如(ru)定位，速(su)度。也有(you)(you)相關(guan)(guan)輸(shu)(shu)出(chu)型，如(ru)跟隨，同(tong)步。相關(guan)(guan)軸可(ke)以是實(shi)際(ji)脈(mo)沖(chong)(chong)(chong)輸(shu)(shu)入計數(shu)值，也可(ke)以是理論計算(suan)的(de)函數(shu)值。常用(yong)的(de)PLC沒有(you)(you)提供兩軸相關(guan)(guan)脈(mo)沖(chong)(chong)(chong)輸(shu)(shu)出(chu)指令。

智能(neng)伺(si)服控制(zhi)(zhi)(zhi)可(ke)(ke)以(yi)不通過命令脈(mo)(mo)沖(chong)。PLC是通過指令，將控制(zhi)(zhi)(zhi)策略變成脈(mo)(mo)沖(chong)，經輸出端口送到伺(si)服驅(qu)動(dong)器，從而控制(zhi)(zhi)(zhi)伺(si)服運行。智能(neng)伺(si)服將控制(zhi)(zhi)(zhi)策略變成寄存(cun)器數據，直接(jie)用數字(zi)來控制(zhi)(zhi)(zhi)伺(si)服運行。與PLC+伺(si)服方(fang)式比較，省(sheng)出了PLC的脈(mo)(mo)沖(chong)輸出口和伺(si)服的脈(mo)(mo)沖(chong)輸入口。在可(ke)(ke)編程單伺(si)服應(ying)用中(zhong)，具有節省(sheng)成本、節省(sheng)安裝(zhuang)工作量、節省(sheng)空間、控制(zhi)(zhi)(zhi)便(bian)利的優(you)勢。當然，智能(neng)伺(si)服也可(ke)(ke)以(yi)接(jie)收外部命令脈(mo)(mo)沖(chong)的控制(zhi)(zhi)(zhi)。