中斷的內(nèi)容有很多種，比如外部中斷、通信中的發(fā)送和接受中斷、定時和計數(shù)的時鐘中斷、還有WDT復(fù)位中斷等，它們豐富了在處理各種事務(wù)時響應(yīng)種類。這樣講也許你并不能完全理解中斷的內(nèi)部結(jié)構(gòu)和操作順序，我們做一個小小的例子來說明.
每一個設(shè)備總是不會忘記有一個按鈕，它也是在我們遇到緊急情況時使用的，那就是急停按鈕。當(dāng)我們遇到人身事故和意外情況時我們只要按下它，機器立即停止所有的操作，并等待處理完意外后再恢復(fù)操作。急停按鈕連接PLC內(nèi)部的內(nèi)部I/O接口上，當(dāng)按鈕給一個外部觸發(fā)信號時，對I/O進(jìn)行再次檢測，當(dāng)確認(rèn)有外部觸發(fā)信號時，保護(hù)現(xiàn)場并將程序計數(shù)器自動轉(zhuǎn)到相應(yīng)的外部I/O中斷程序中去，當(dāng)外部中斷程序處理完畢，程序計數(shù)器返回到主程序繼續(xù)工作。有一點可以說明的是我們一般會把急停按鈕的外部中斷升至別，從而保證。
當(dāng)我們在工作完一個工件時，給PLC一個信號，將PLC的內(nèi)部計數(shù)器加1來計算我們的工作量時，一個簡單的計數(shù)器能解決問題，當(dāng)然它們也能夠在掉電的情況下保持?jǐn)?shù)據(jù)，促使數(shù)據(jù)不丟失，這也是我們所渴望的。
PLC還具有計數(shù)器的功能，當(dāng)我們在接受一些高速的數(shù)據(jù)時，這里所說的高速是在在微秒級的數(shù)據(jù)，比如條碼掃描機在不斷的掃描數(shù)據(jù)，數(shù)據(jù)處理器DSP計算的高速信號等，我們就要采用到計數(shù)器來幫助我們進(jìn)行計數(shù)。它在PLC執(zhí)行程序時一旦發(fā)現(xiàn)計數(shù)器對應(yīng)的中斷，就會立即放下手上的工作。經(jīng)過再次編程的梯形圖程序說明我們在執(zhí)行程序時計數(shù)器會自動的執(zhí)行對應(yīng)的工作，從而將計數(shù)器的級別升至高一級別。
Allen Bradley NEMA size 4 Reversing Starter Vertical Mount
ALLEN BRADLEY MPL-B660F-SJ22AA MPLB660FSJ22AA
ALLEN BRADLEY I/O BLOCK 1791-24A8 SER. B * IN BOX*
ALLEN BRADLEY HIGH PERFORMANCE AC DRIVE 1392-B150-RL-MC-B-F2 SER. A
ALLEN BRADLEY F-6300-R-H04AA SERVO MOTOR
Allen Bradley Bulletin 1336 Dynamic Brake 1336-MOD-KB050 Series D
Allen Bradley AC Servo Motor with Brake 1326AB-B740C-21-K7
ALLEN BRADLEY AC POWER F-8A/250V FREE SHIPPING
Allen Bradley AC DRIVE MOD.1336S B040 AAENS-L6
ALLEN BRADLEY 83003C1J1 83003C1J1
ALLEN BRADLEY 8200014735 8200014735
ALLEN BRADLEY 8200014700 8200014700
ALLEN BRADLEY 810-A24A 810A24A
ALLEN BRADLEY 8000-PG2 8000PG2
ALLEN BRADLEY 6500-PS7DSP 6500PS7DSP
ALLEN BRADLEY 6181-CHDCBBZZR 6181CHDCBBZZR
ALLEN BRADLEY 6181-CEBBBBZZZ 6181CEBBBBZZZ
ALLEN BRADLEY 6181-AHBCBBEZZ 6181AHBCBBEZZ
ALLEN BRADLEY 6181-ABBBAAZZZ 6181ABBBAAZZZ
Allen Bradley 6155R-14P2KH VersaView 1400R Computer, Series A, Rev C *EXCELLENT*
Allen Bradley 5820-EI | Tested with 12 month warranty
ALLEN BRADLEY 5730-CPU1 VMS PROCESSOR MODULE 5730CPU1
ALLEN BRADLEY 5730-CPU1 VMS PROCESSOR MODULE 5730CPU1
ALLEN BRADLEY 520VF-EOD TWO-SPEED SIZE 4 MULTI-SPEED MOTOR STARTER B443907
ALLEN BRADLEY 513-CCB-C1K-6XP-44-90011 513CCBC1K6XP4490
Allen Bradley 509FOS NSNP **GENUINE** AB 509 FOS
ALLEN BRADLEY 501587 501587
ALLEN BRADLEY 50/60HZ 3PH 2500-5000V 800A VACUUM CONTACTOR 1502-V8C6D1 SER. A
ALLEN BRADLEY 445L-T4L1800YD 445L-R4S1800YD 445L-T4S1800YD LIGHT CURTAIN
ALLEN BRADLEY 4100-232-R SERIES P IMC S CLASS 2 AXIS MOTION CONTROLLER (W4)
Allen Bradley 409F304ND **GENUINE** AB
Allen Bradley 3400-TFS Power Supply
ALLEN BRADLEY 2755-L4RDA 2755L4RDA
ALLEN BRADLEY 2750-ASD1, Intelligent Antenna, REV. B, SER. D,
Allen Bradley 2711-T14C8, Series A, Panelview 1400, Rev D, FRN 4.41
ALLEN BRADLEY 2711-T10C8 SERIES D PANELVIEW 1000 100-240 VAC 0.4-0.25A,
Allen Bradley 2711-T10C16 Series D AB 2711T10C16/D PanelView 1000
ALLEN BRADLEY 2711P-RDT10C SERIES B OPERATOR INTERFACE W/ 2711P-RP1 LOGIC MODULE
ALLEN BRADLEY 2711-PK7C6A1 2711PK7C6A1
Allen Bradley 2711P T10C4D9 Panel View Plus, HMI, Operator Interface
ALLEN BRADLEY 2711-K5A8 SER.H OPERATOR TERMINAL * IN A BOX*
Allen Bradley 2711-K10G8 /E PanelView 1000 Gray Key/DH+/RS-232-Prt FRN 4.46
ALLEN BRADLEY 2711-B5A10 2711B5A10
ALLEN BRADLEY 2711-B5A1 2711B5A1
ALLEN BRADLEY 22C-D260A103 POWERFLEX 400 SER. A, 200HP, 480V, 22CD260A103
ALLEN BRADLEY 20B-D-065-A-3-AYNANCO SERIES B 50HP **
ALLEN BRADLEY 20BD040A0AYNANC0NNAD 20BD040A0AYNANC0
Allen Bradley 20BD034A0AYNADA0 Ser A Powerflex 700 AC Drice 480vac 3 Phase
ALLEN BRADLEY 20BD027A3AYNANC1 20BD027A3AYNANC1
Allen Bradley 20BD011A3AYNACC1 Ser A Powerflex 700 AC Drice 480vac 3 phase
ALLEN BRADLEY 20A D 052 A 3 AYNANC0 A POWERFLEX 70 40HP AC DRIVE
ALLEN BRADLEY 2098-IPD-HV050-DN 2098IPDHV050DN