3HAC17328-13HAC17328-1

PLC的工作原理
    PLC是一種工業(yè)控制計(jì)算機(jī)，它的工作原理建立在計(jì)算機(jī)工作原理之上，即通過執(zhí)行反映控制要求的用戶程序來完成。
1.4.1   PLC可編程控制器的基本工作原理
    PLC以微處理器為核心，具有微機(jī)的許多特點(diǎn)，但它的工作方式卻與微機(jī)有很大不同。
微機(jī)一般采用等待命令的工作方式工作。
    PLC是按集中輸入、集中輸出，周期性循環(huán)掃描的方式進(jìn)行工作的。每一次循環(huán)掃描所用的時(shí)間稱為一個(gè)掃描周期。
    對(duì)每個(gè)程序，CPU從*條指令開始執(zhí)行，按順序逐條地執(zhí)行指令做周期性的程序循環(huán)掃描，如果無跳轉(zhuǎn)指令，則從*條指令開始逐條順序執(zhí)行用戶程序，直至結(jié)束又返回*條指令，如此周而復(fù)始不斷循環(huán)。
    PLC在每次掃描工作過程中除了執(zhí)行用戶程序外，還要完成內(nèi)部處理、輸入采樣、通信服務(wù)、程序執(zhí)行、自診斷、輸出刷新等工作。PLC工作的全過程包括三個(gè)部分，即上電處理、掃描過程和出錯(cuò)處理。PLC工作的全過程可用圖4所示的運(yùn)行框圖來表示。
    手機(jī)

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 Qq:

鄭娟萍

廈門仲鑫航自動(dòng)化設(shè)備有限公司

在圖4中，PLC通電后，CPU在系統(tǒng)程序的控制下*行內(nèi)部處理，包括硬件初始化、I/O模塊配置檢查、停電保持范圍設(shè)定及其他初始化處理等工作。
    PLC有很強(qiáng)的自診斷功能，PLC每掃描一次執(zhí)行一次自診斷檢查，確定PLC自身的動(dòng)作是否正常，如電源檢測(cè)、內(nèi)部硬件是否正常、程序語法是否有錯(cuò)等。如檢查出異常時(shí)，CPU面板的LED及異常繼電器會(huì)接通，在特殊寄存器中會(huì)存入出錯(cuò)代碼；CPU能根據(jù)錯(cuò)誤類型和程度發(fā)出信號(hào)，甚至進(jìn)行相應(yīng)的出錯(cuò)處理，使PLC停止掃描或強(qiáng)制變成STOP狀態(tài)。
    PLC運(yùn)行正常時(shí)，掃描周期的長短與用戶應(yīng)用程序的長短、CPU的運(yùn)算速度、I/O點(diǎn)的情況等有關(guān)。通常用PLC執(zhí)行1KB指令所需時(shí)間來說明其掃描速度（一般1-10ms/KB）。值得注意的是，不同指令執(zhí)行時(shí)間是不同的，故選用不同指令所用的掃描時(shí)間將會(huì)不同。若用于高速系統(tǒng)要縮短掃描周期時(shí)，可從軟硬件上同時(shí)考慮。PLC周期性循環(huán)掃描工作方式的顯著特點(diǎn)是：可靠性高、抗*力強(qiáng)，但響應(yīng)滯后、速度慢。

Dodge Taper Lock Bushing 3020x1-15/16 3020 1-15/16" Keyed Bore 117117 NEW

TB Wood's 7S 1-5/16 Coupling Flange 7Sx1-5/16 7S1516

NEW MARTIN 2012 1-7/16 BUSHING BORE SIZE 1-7/16" 20121716

NEW DODGE 1615 TAPER LOCK BUSHING BORE SIZE 15/16 161515/16

Martin 40L050 SDS QD Timing Pulley 40L050SDS New

No Name Timing Pulley 40L100SDS Max RPM 5270 New

BARUFFALDI 034995 INDUSTRIAL DC MOTOR CLUTCH NEW 

NEW T&B 3994 3" INSULATED GROUNDING BUSHING / BLACK LINED 

TB Wood's 5J12 SF Coupling Flange 5Jx1/2 5J 1/2" New

MARTIN TIMING PULLEY P2814M40-SK  P2814M40SK

NEW DODGE KEYED SPLIT TAPER LOCK BUSHING 1210 3/4" BORE 

New Browning Hub L110X 1 3/8 L110X13/8 L110

NEW TB WOODS TL2012138 TL BUSHING 2012 1-3/8 TAPER LOCK

NEW TB WOOD'S SF42MM SG BUSHING SF 42 MM XL x 5

Maurey Pulley BC-98 BC98 5/8" Bore New

Masterdrive 2 Groove Sheave Pulley 2/3V365SH 23V365SH New

Browning 3 Groove Sheave Pulley 3TB58 with Keyed Bore 6" OD New

NEW ELECTRON 60S 60 S TIMING PULLEY 

Ametric Bushing MZ3502 2012 20 2101220 New

GATES 78241421 60H200SF 60 H 200 SF TIMING PULLEY NIB

Rexroth Linear Ball Bearing Bushing 0750-212-00 075021200 New

NEW BROWNING V-BELT PULLEY SHEAVE 1H3V36 1 GROOVE

Martin Tapered Bushing 2012 1 7/16 2012X1-7/16 20121716 1 7/16" Bore 3/8" KW NIB

Martin Tapered Bushing 1610 1 3/8 1610138 1610X1-3/8 1 3/8" Bore 5/16" KW New

NEW MARTIN 2B3.4 SH 2 GROOVE PULLEY SHEAVE 11234 2B34SH 2B34

BROWNING 2 BELT PULLEY SHEAVE EN6191 EN-6191 NEW

Falk Coupling Hub 70T 2" Bore New

NEW MARTIN SK 15/16 BUSHING 15/16" BORE SK1516

MARTIN 5 B 70 SF 5B70SF 5V 5 V PULLEY SHEAVE NIB

Maska Split Tapered Bushing SD X 1-7/8 SDX178 1-7/8" Bore New

NEW FCI 82006594 BEARING SLEEVE 

NEW FCI 82059544 BEARING SLEEVE 

No Name Keyed Timing Pulley Z 15 Z15 New

Browning Timing  Pulley 24HB100 24 Teeth .75" 3/4 Bore Diameter

BROWNING 3 GROOVE SHEAVE 6 3/4" O.D. 6.75" OD 3Q3V69

NEW TB WOOD'S J 3-7/8 QD BUSHING J 37/8 J378

NO NAME PAP 50 40 P10 SLIDING BUSHING NEW

HP Hewlett Packard VX Laser Toner Cartridge 5MP,5P,6MP

NEW MARTIN QD TIMING PULLEY 20L100 JA 20L100JA

Morse Bushing 604307 700TL 700 TL (810)PB

 New Browning BK34H Split Taper Bushed Groove Pulley

Martin Split Taper Bushing P1 1 7/16 P11716 P1X1-7/16 1 7/16" Bore 3/8" KW New

NEW BROWNING SPLIT TAPER KEYED BORE BUSHING Q1 X 3/4 Q134 3/4" BORE 

BROWNING R1 42 MM SPLIT TAPER BUSHING NIB

Barksdale HVAC Control Switch Fully Adjustable D3S-AA2 D3SAA2 83.3"H2O 1/4"Npt

New Gates QD Multi-Duty Sheave 3A6.0/B6.4SD QD3A604B64

MARTIN 3 C 75 SF 3C75SF CONVENTIONAL QD SHEAVE NIB

NEW KOYO BEARING 6210RS 

TB Woods SF 3/4" Bushing SF34

NEW NO NAME 2 GROOVE KEYED SHEAVE PULLEY 90 2SPA 902SPA

New Browning Bushing SK 1 11/16 SK 1-11/16 SK111/16

NEW BROWNING SHEAVE OK40-3/4"  3/4" OK4034 

Electron Keyed Bushing SH X 38mm 1 1/2" SH38MM New

Maska Sheave Pulley 1-3V6.00 SH 13V6.00SH 13V600SH 1 Groove New

NEW MARTIN TIMING PULLEY TL30L075 1610 

Ametric Timing Pulley  36 H 100 1610 36H100 1610 36H1001610 New

NEW LOT OF 4 NO NAME GALVANIZED REDUCER  HEX BUSHING1/2" MALE 1/4" FEMALE 

MARTIN BUSHING 2012 BORE SIZE 3/4" 20123/4 NEW

TAPER LOCK BUSHING, SIZE 1210, BORE 7/8" NEW

BROWNING AK59X1/2 AK59 X 1/2 BELT PULLEY NEW

TB Woods Timing Pulley 26L075-SH 26L075SH New 

NEW TB WOOD'S SK 1-1/16 BUSHING SK X 1 1/16 

Martin QD Bushing SD 15/16 SD1516 15/16" Bore New

Woods 4 Groove V-Belt Sheave 3V4.5X5SDS 3V 4.5 4 SDS 3V454SDS New

NEW BROWNING 3 GROOVE PULLEY 3MVB80Q

Browning Split Tapered Bushing Q2 2 1/2 Q2212 2-1/2" Bore Keyed NIB

NEW WOODS SPLIT TAPER KEYED BORE BUSHING SF 1-3/4 1-3/4" BORE

NEW MOLINE TAPERED LOCK BUSHING 3535 3" BORE 

NEW DODGE TAPER LOCK BUSHING 117087 2012 5/8 201258 2012 X 5/8 5/8" Bore 

Martin Timing Pulley P3614M55 2517 New

 TB Woods Tapered QD Sure Grip Bushing SH X 1 1/4 S QA E SHX114 w/ hardware New

NEW MASKA 3-5V 13.2E 3 GROOVE PULLEY SHEAVE 13-1.4" OD 

NEW DAYCO SYNCHRO-COG 420 L 050 TIMING BELT 420L050 1/2"WIDE

BROWNING BK150H One Groove Sheave BK-150-H New

ROSE MFG SAFETY PULLEY 506222 300LB 300 lb 

NEW MARTIN 3 BELT SHEAVE 35V800

MasterDrive Two Groove V Belt Pulley Sheave 664064 5 3/4" OD New

ROMARSH 3R750/1 252-40-05 120HH 115A TRANSFORMER

NEW BROWNING PULLEY 3 GROOVE 3R5V97 

LENZE-D 14.115.06.10 ELECTROMAGNETIC CLUTCH 141150610 24VDC 11.5W 7.5NM

NEW MARTIN F 1 7/8 BUSHING 1-7/8" BORE F178

NEW MARTIN 1615 1 1/2 TAPER BUSHING 1615112 1-1/2" KEYED BORE

Martin Miter Gear HMK1025B 1" Keyed Bore New

NEW BROWNING R1 3 3/8 SPLIT TAPER BUSHING R1338

Dodge Taper Lock Bushing 117159 1610 x 1 KW 1" Bore  New

Dodge Dyna Sync Timing Pulley 113468 TL28L050-1210 TL28L0501210 SY 11770RPM New

No Name SK 1-1/16" QD BUSHING SK1116 SKx1-1/16

NEW BROWNING 2 GROOVE V-BELT SHEAVE PULLEY 2TB50

NEW NO NAME SYNC PULLEY 48L100

Martin Split Taper Bushing SDS 1-7/16 SDSX1-7/16 SDS1716 1 7/16" Bore 3/8" KW 

NEW TB WOOD'S 5.6 X 1B SDS TXF SHEAVE 561B SDS RPM 4200

NEW NO NAME 6/5V 9.75 3535 6 GROOVE SHEAVE MAX RPM 2600 CD 6 5V 9.75 9-3/8" OD

TB Woods Split Taper Bushing SDS 1-1/16 SDS1116 1-1/16" Bore New

Martin Split Taper Bushing SF 1-15/16 SF11516 1-15/16" Keyed Bore New

AMERICAN LED-GIBLE S0-8814-001 S08814001 PRODUCTION PACER PACE TIMER DISPLAY

Dodge Taper-Lock Bushing 2517 5/8 251758 5/8"Bore New

New Martin Sheave 2 B 60 TB 2B60TB

NEW MARTIN KEYED BORE BUSHING 2012 1 7/16" BORE

BROWNING 1TC80 1 GROOVE SHEAVE NEW 

 NEW DODGE TAPER LOCK BUSHING 1615  3/4  161534 1615 3/4 161534 

2 NEW B-LOC 2-7/16 / B400-IN LOCKING ASSEMBLY 2-7/16"

NEW MAUREY 2QH 150 SH TIMING PULLEY 2QH150SH 

Ametric Bushing 2012 19 210119 Bore Size 19 New

TRANTORQUE 1 3/16" BUSHING FENNER MANHEIM 6202300 NEW

NEW GATES P40-8M-20 SH POWERGRIP HTD SPROCKET TIMING PULLEY 7825-0028 40-8M-20SH

Martin QD Bushing SDS 1 1/16 SDS1116 1-1/16" Bore New

No Name Split Taper Bushing SK X 1 3/8 SKX138  SK138  1-3/8" Bore New

NEW BROWNING ONE GROOVE PULLEY AK20 X 3/4" BORE AK2034 MAX RPM 12410

NEW TB WOODS CONVENTIONAL SHEAVE 462B 4.6X2B-SDS 462BSDS MAX RPM 5050

NEW DODGE T-L SHEAVE 112190 2/3V4 12-1610 2/3V412-1610

NEW TL SPLIT TAPER BUSHING 1008 14MM BORE CH3

Bando American TL24H100 1610 MB Timing  Pulley

DODGE TAPER LOCK BUSHING 2012 1-5/8" KW 117092 New

New TB Woods Wood's Wood Flange 3J 7/8 3J-7/8 7/8"

NEW TB WOODS SF 2-1/8 BUSHING SFX2-1/8 SF218

No Name Keyed Bore Bushing 1615 40MM 161540MM 161540 40mm 40 mm New

DODGE TAPER-LOCK BUSHING 119012 1215X1-3/16  NEW 

TB WOODS SDS-1 7/16 RLV SDS1716 SDS 1 7/16 BUSHING NEW

DODGE BUSHING 117167 2012 X 7/16" TAPER LOCK BUSH NEW

Dodge 119615 T-L Bushing 2012 X 40mm 201240MM 201240 40 mm 119615 New

LOT OF 5 Tube Tex Bushings  A1403200 TE002 

DODGE TAPER-LOCK BUSHING 117073 1008 x 5/8" KW 

Gates Keyed Bore Taper Lock Bushing 1215 1-1/4 1215114 1-1/4" Bore New

Dodge Taper-Lock Bushing 1215 3/4 121534 3/4" Bore New

New Dodge Taper-Lock Bushing 1210x 15/16 kw 119198

New TB Woods Wood's Wood Sure Flex Spacer Hub 5SC-Hx1 5SCHx1 1"

NEW TB WOODS SK 1-1/2 KEYED BUSHING SK 1-1/2 S SK 1-1/2 1-1/2" BORE 

NEW Dodge Taper-Lock bushing 2012 13/16 kw 119246

Maska Single Groove Sheave Pulley MA25 1/2" Unkeyed Bore New

Unknown Brand Lot of 6 Bushings PG 30 34 40 F PG303440F

Fenner Taper Lock Bushing Bore sz 2517 050 029M0050 NEW

NEW NO NAME BRASS BRONZE BUSHING 2"ID 2-1/2"OD 23/32"WIDTH

CLARK TKS 303170 INNER RAIL ROLLER BUSHING 303170

Factory Authorized Parts Bushing 19 C 47 2471 19C472471

DODGE 1615 X 7/8 TAPER LOCK BUSHING 119046 NEW

New Browning Bushing SF 2 SF2 2" Bore

Martin Timing Pulley TB24H200 2012 TB24H2002012 New

Flowserve Balance Bushing 896379 54270848 7344601-10 869379 716638 New

TB WOODS SG BUSHING SDS1316 SDSX1 3/16 NEW

NEW BROWNING BUSHING B 1 3/4" B 1 3/4

TB Wood's 10Sx1-5/8 Coupling SF Flange 10S158 1-5/8"

MASKA CAST IRON SHEAVE MA53X5/8 MA53 OD 5 1/4 5.25 NEW

NEW NO NAME TIMING PULLEY TL22L100 1108RS

NEW TB WOOD'S 5.8 X 2B SDS SHEAVE MAX RPM 4250T 582BSDS

NEW UNIROYAL POWER GRIP 390 L 050 TIMING BELT 390L050 1/2"WIDE 

NEW DODGE SYNC PULLEY TL48L050-2012 TL48L0502012  MAX RPM 4450

Dodge Steel Split Pulley Green 203018 4X6 CR New

BROWNING 44HQ100 GEARBELT PULLEY TIMING GEAR 3" BORE 7 1/4" DIAMETER NIB

BROWNING 1-5/8" PULLEY SHEAVE 1VP75A VP75A NEW

DODGE Q.D. SHEAVE 455126 2 GR 3V 2.8-JA BUSH 2 GROOVE NEW

MARTIN BUSHING J-4-7/16 J4716 J4 7/16 NEW

TB WOOD'S L100 1-1/4" TFH L-JAW COUPLING L-100 NEW

NEW T.B. WOODS SURE -GRIP TIMING PULLEY 60H100

NEW SST KEYED SPLIT TAPERED BUSHING Q1 2 7/16 Q12716 2 7/16" BORE

Lovejoy Flat Companion Sheave 2.75F10SD 275F10SD 10" OD 2-3/4" W New 

Browning Bushing Q1-1 5/8 Q1158 1-5/8" New

NEW Dodge 117175 2517 x 2-3/16 KW Taper Lock Bushing 2517 2-3/16 KW  25172316

+GF+ GEORGE FISCHER REDUCER BUSHING 837-420 SCH. 80 PVC 4" x 2" 4 IN x 2 IN 

NEW FCI 82078528 BEARING SLEEVE 

Westinghouse Circuit Breaker LC3600F 3P 600A 600 A Amp 600 VAC w. 600 Amp Trip

New TB Woods Bushing EX1-3/4 EX 1-3/4 

NEW MASKA QD BUSHING SDS X 2 SDSX2

Martin Pulley 1B80SDS 1 B 8.0 SDS 1 B 80 SDS B80

NEW TB WOOD'S SF 1-3/4 SS SURE-GRIP QD BUSHING SF134

NEW DODGE POLY DISC FLANGE ASSEMBLY 1210 3-1/4H 

Martin Unkeyed Sprocket 41B36 36 Teeth 5/8" Bore New

NEW DODGE TAPER-LOCK BUSHING 117150 1008 X 3/4 KEYWAY "LOT OF 3"

MARTIN TAPER LOCK BUSHING 3535 2-5/8" NIB

NEW WOOD'S BUSHING SD X 3/4" BORE

No Name Timing Pulley 28H200SD New

MARTIN 3030 1 5/8" BORE BUSHING NIB

Dodge Bushing 3020 X 2-1/8 KW 3020218 KW 2-1/8" Bore New

No Name Taper Lock Bushing 1615 X 1-5/16 16151516 1-5/16" Bore New

NEW TB WOODS SK X 40MM BUSHING SKX40MM 1-9/16" 40mm BORE 

Lot of 2  Dodge Taper Lock Bushing 119191 1210x1/2 1210 x 1/2 KW 1210x1/2KW NEW

TB Woods Timing Pulley 32H100 32 H 100-SK 32H100SK 4970RPM New

No Name Timing Pulley 24HB200 New

NEW NO NAME BRASS BRONZE BUSHING 25/32" ID 1-1/32" OD "LOT OF 2"

Browning Single Groove Sheave BK30 1/2" Bore Lot of 2 New

NEW WOOD'S SURE-GRIP BUSHING SDS X 1/2" BORE

NEW PLUMMER SPRAY BUSHING BP-0526 BP0526 LOT OF 12

Fenner Taper Lock Bushing bore sz 1615028 029110028 NEW

Martin Taper Bushing 2012 42MM New

NEW NO NAME TAPER LOCK BUSHING G-34 3/11 X 3/32 KS 32012

NEW LOT OF 2 B-LOC LOCKING ASSEMBLY B400  50X80

New Browning Bushing 40P18 1.865" Bore

NEW FCI 82000969 BEARING SLEEVE 

NEW TB WOOD'S 8S1 COUPLING FLANGE 8S X 1 RPM 4500 TGF%2

No Name Timing Belt Pulley 56-8M 30SDS 568M30SDS New

BROWNING Q1X25MM SPLIT TAPERED BUSHING 8 X 3.5 KW NIB

NEW LOT OF 3 BKB BLACKBURN SPLIT BOLT CONNECTOR 4H 8-4 SOL 2.5-16

SKF Rubber Sealed Roller Ball Bearing 22207CC/C2W33 22207CC C2W33 New