產(chǎn)品詳情
在PLC控制系統(tǒng)中,電源占有極重要的地位。電網(wǎng)干擾串入PLC控制系統(tǒng)主要通過PLC系統(tǒng)的供電電源(如電源、I/O電源等)、變送器供電電源和與PLC系統(tǒng)具有直接電氣連接的儀表供電電源等耦合進(jìn)入的?,F(xiàn)在,對(duì)于PLC系統(tǒng)供電的電源,一般都采用隔離性能較好電源,而對(duì)于變送器供電的電源和PLC系統(tǒng)有直接電氣連接的儀表的供電電源,并沒受到足夠的重視,雖然采取了一定的隔離措施,但普遍還不夠,主要是使用的隔離變壓器分布參數(shù)大,干擾能力差,經(jīng)電源耦合而串入共模干擾、差模干擾。所以,對(duì)于變送器和共用信號(hào)儀表供電應(yīng)選擇分布電容小、帶大(如采用多次隔離和屏蔽及漏感技術(shù))的配電器,以減少PLC系統(tǒng)的干擾。
位保證電網(wǎng)饋點(diǎn)不中斷,可采用在線式不間斷供電電源(UPS)供電,提高供電的安全可靠性。并且UPS還具有較強(qiáng)的干擾隔離性能,是一種PLC控制系統(tǒng)的理想電源。
2電纜選擇的敖設(shè)
為了減少動(dòng)力電纜輻射電磁干擾,尤其是變頻裝置饋電電纜。筆者在某工程中,采用了銅帶鎧裝屏蔽電力電纜,從而降低了動(dòng)力線生產(chǎn)的電磁干擾,該工程投產(chǎn)后取得了滿意的效果。
上世紀(jì)60年代后期,根據(jù)當(dāng)時(shí)汽車市場(chǎng)需求和計(jì)算技術(shù)的發(fā)展,在美國(guó)麻薩諸塞州Bedford的Bedford Associates,向美國(guó)汽車制造業(yè)提議開發(fā)一種Modular Digital Controller(MODICON)取代繼電控制盤。其它一些公司也建議以計(jì)算機(jī)為基礎(chǔ)的方案。其核心思想是采用軟件編程方法代替繼電控制的硬接線方式,并備有生產(chǎn)現(xiàn)場(chǎng)大量使用的輸入傳感器和輸出執(zhí)行器的接口,以便于進(jìn)行大規(guī)模生產(chǎn)線的流程控制。這就是以后被稱為Programmable Logic Controller的由來。MODICON 084是世界上種投入商業(yè)生產(chǎn)的PLC。
0年代是PLC崛起,首先在汽車工業(yè)獲得大量應(yīng)用,在其它產(chǎn)業(yè)部門也開始應(yīng)用的時(shí)期。80年代是它走向成熟,采用微電子及微處理器技術(shù);大量推廣應(yīng)用,并奠定其在工業(yè)控制中不可動(dòng)搖地位的時(shí)期。在此階段PLC銷售始終以兩位數(shù)百分點(diǎn)的速度增長(zhǎng),前六年的增長(zhǎng)率超過35%,后四年穩(wěn)定發(fā)展,年增長(zhǎng)率約12%。90年代又開始了它的第三個(gè)發(fā)展時(shí)期。隨著PLC的IEC 61131的正式頒布,推動(dòng)了PLC在技術(shù)上發(fā)動(dòng)新的突破:在系統(tǒng)體系結(jié)構(gòu)上,從傳統(tǒng)的單機(jī)向多和分布式及遠(yuǎn)程控制系統(tǒng)發(fā)展;在編程語言上,文本化和圖形化的語言多樣性,創(chuàng)造了更具表達(dá)控制要求、文字處理、通信能力的編程環(huán)境。
從應(yīng)用范圍和應(yīng)用水平上,除了繼續(xù)發(fā)展機(jī)械加工自動(dòng)生產(chǎn)線的控制系統(tǒng)外,則是發(fā)展以PLC為基礎(chǔ)的DCS系統(tǒng)、監(jiān)控和數(shù)據(jù)采SCADA系統(tǒng)、柔性制造系統(tǒng)(FMS)、安全聯(lián)鎖保護(hù)(ESD)系統(tǒng)、運(yùn)動(dòng)控制系統(tǒng)等,地產(chǎn)提高PLC的應(yīng)用范圍和水平。
進(jìn)入90年代后期,由于用戶對(duì)開放性的強(qiáng)烈要求和壓力,由于信息技術(shù)的大力推動(dòng),PLC如果還停留在原有的專用而又封閉的系統(tǒng)概念上,它將坐以待斃。于是PLC進(jìn)入了其發(fā)展的第四階段。其特征是:
HAM-LET UNION ELBOW 1/2T HEX-BODY SST SV4 LOT OF 2
HANNIFIN SST-2 NSPP SST2
HANNIFIN SST-4 SST4
HCAK204-12 SST Ball Bearing Pillow Block
HCAK205-16 SST Ball Bearing Pillow Block
HCAK207-22 SST Ball Bearing Pillow Block
HCAK207-23 SST Ball Bearing Pillow Block
HCAK208-25 SST Ball Bearing Pillow Block
HCAK209-26 SST Ball Bearing Pillow Block
HCAK209-28 SST Ball Bearing Pillow Block
HCFS208-24 SST Ball Bearing Flange Unit
HCFT205-16 SST Ball Bearing Flange Unit
HCFT207-22 SST Ball Bearing Flange Unit
HCP204-12 SST Ball Bearing Pillow Block
HCP205-14 SST Ball Bearing Pillow Block
HCP205-16 SST Ball Bearing Pillow Block
HCP206-20 SST Ball Bearing Pillow Block
HCP207-22 1-3/8" SST Ball Bearing Pillow Block -
HCP207-22 1-3/8" SST Ball Bearing Pillow Block -
HCP207-23 1-7/16" SST Ball Bearing Pillow Block -
HCP207-23 1-7/16" SST Ball Bearing Pillow Block -
Helical 1/4" x 1/2" Vari. Pitch High Perf. Carbide End Mill w/C.R-SST,Titanium
Helical 1/4" x 1/2" Vari. Pitch High Perf. Carbide End Mill w/C.R-SST,Titanium
Helical 1/4" x 3/4" Vari. Pitch High Perf. Carbide End Mill w/C.R-SST,Titanium
Helical 1/4" x 3/8" Vari. Pitch High Perf. Carbide End Mill w/C.R-SST,Titanium
Helical 1/4" x 3/8" Vari. Pitch High Perf. Carbide End Mill w/C.R-SST,Titanium
Helical 1/8" x 1/2" Vari. Pitch High Perf. Carbide End Mill w/C.R-SST,Titanium
Helical 1/8" x 1/4" Vari. Pitch High Perf. Carbide End Mill w/C.R-SST,Titanium
Helical 3/16" x 5/8" Vari. Pitch High Perf. Carbide End Mill w/C.R-SST,Titanium
Helical 3/16"x5/16" Vari. Pitch High Perf. Carbide End Mill w/C.R-SST,Titanium
Helical 3/8" x 1/2" Vari. Pitch High Perf. Carbide End Mill w/C.R-SST,Titanium
Helical 5/16" x 1/2" Vari. Pitch High Perf. Carbide End Mill w/C.R-SST,Titanium
HIGH QUALITY 1"OD x 0.834"ID x 30" SST 304 Stainless Steel Tube SEAMLESS
HIGH QUALITY 1"OD x 0.87"ID x 36" SST 304 Stainless Steel Tube SEAMLESS
HIGH QUALITY 1.25"OD x 0.938"ID x 19" SST 304 Stainless Steel Tube SEAMLESS
HIGH QUALITY 1.25"OD x 0.938"ID x 30" SST 304 Stainless Steel Tube SEAMLESS
High Quality 400 MESH 12"X12" FILTRATION SS T316 FREE SHIP
HK SYSTEMS .. 4 BOLT CAST IRON HOUSING.. SST XB206-19 C3 KY PILLOW BLOCK BEARING
HK SYSTEMS 4 BOLT FLANGE PILLOW BLOCK C12000, XB206-19, SST, 1-1/8" BORE
HM89446 SST Taper
HOKE 2315F4Y 2300K1 sst control valve with presicion handle * NO BOX*
HOKE 2315F4Y sst 3000 psi control valve * NO BOX*
HOKE 316SST BALL VALVE 2000 PSI 7092G8Y (AISLE B)
HOKE 7387004S MANIFOLD VALVE 316 SST 832
HOKE 7387004S MANIFOLD VALVE 316 SST 832
Hoke Gyrolok 16U316, SST, 1" Union Ref Swagalok Ss-1610-6, 772LSS1, Z#19
Hoke Selecto-Mite 316SST Ball Valve Model 7165F4Y
Hot 10 Packs Dental Endo K-FILE 010/10 Purple 25mm SSt DENTSPLY MAILLEFER CE
HUMMINGBIRD XETRON ( FCC ID:MH9-SST900A)
HUMMINGBIRD-XETRON-FCC-ID-MH9-SST900A
HUMPHREY 6-DP-2 PNEUMATIC CYLINDER 1 1/16 inch bore 2" Stroke SST
HUMPHREY 6-DP-2 PNEUMATIC CYLINDER 1 1/16 inch bore 2" Stroke SST
HYPERTHERM #020940 RETAINING CAPACITY PAC180 30A SST STK 4433
HYPERTHERM #020940 RETAINING CAPACITY PAC180 30A SST STK 4433
Hypertherm 100A SST Inner Retaining Cap 120592 for HD1070 HD3070 Qty: 1
HYPERTHERM 220608 260A SST BEVEL
HYPERTHERM 220608 260A SST BEVEL
Hypertherm Electrode 80A SST - High Perbance - 220339
IC SST 31LF021 70-4C-WH 2 Mbit Flash 70ns & 1 Mbit SRAM 70ns ComboMemory 32-TSOP
IC SST 36VF3203 ND FLASH MPF 32MBIT (x8/x16) 70NS TFBGA48 (6mm x 8mm) 2.7V~3.6V
IC SST 37VF040 70-3С-NHE MT FLASH MPF 4 Mbit (x8) 70NS 32-pin PLCC 2.7V ~ 3.6V
IC SST 39VF6402B 70-4I-EKE ND FLASH MPF 64MBIT (4M x 16) 70NS 48TSOP 2.7V ~ 3.6V
IC SST 55LD019M ATA Flash Disk Controller 5.0V or 3.3V host interface TQFP-100
ICO RALLY SST-26 RED PTFE TEFLON TUBBING 26AWG,RED ROLL OF APPROX 100FT
Ideal-Tridon 300200575051 SS T-Bolt Channel Bridge Hose Clamp 146.1 mm - 10Pack
INDUSTRIAL RETAINING RINGS # 5000-0200SST PK OF 4 INTERNAL SNAP RINGS
INDUSTRIAL RETAINING RINGS # 5000-475SST INTERNAL SNAP RINGS
INDUSTRIAL RETAINING RINGS # 5555-50SST PK OF 24 EXTERNAL SNAP RINGS
INTEGRATED CONTROL 1213C SENSOR FL SST 1/4 FVCR STK G
INTELLIFEED 890025-404 8-1/2 IN LENGTH SST ROLLER CONVEYOR REPLACEMENT B469615
INTERMATIC K4536SST Photocontrol,Locking,105 to 305VAC
INTERMATIC PHOTO CONTROL K4536SST//105-305V
John Deere JD SST15 Spin Steer Mower Tractor Operators Manual
John Deere SST15 SST16 SST18 Spin Steer Lawn Tractor operators manual JDL2
John Deere SST16 SST18 SST 16 18 spin steer tractor owners & maintenance manual
Jonard Industries SST-916 9/16" Security Shield Tool
JONARD SST-916 Security Shield Tool, Steel
JONARD SST-916 Security Shield Tool, Steel
JOSEPH SST-1.12X1.00-4 AIR PNEUMATIC CYLINDER
K&S PRECISION METALS 7140 Round Rod, SST, 1/4in Dia. x 36 In. L, PK4
K&S PRECISION METALS 7142 Round Rod, SST, 5/16in Dia. x 36 In. L, PK3
K&S PRECISION METALS 7144 Round Rod, SST, 3/8in Dia. x 36 In. L, PK3
KAMLOC 1" SST 634-B OPW TWIN KAM CAP
KAMLOC 2" SST 634-B OPW TWIN KAM CAP
KAMLOC 3" SST 634-A MALE CAP OPW
Kamlock Stainless Steel SST 633-D Quick Coupling 1" Female Threaded
KAMLOK * 1" SST TWIN KAM * 733-DL
KAMLOK 5/16 F-05-C SST - OPW TWIN-KAM STAY DOWN ARMS HOSE SHANK
KAMLOK 5/16 F-05-C SST - OPW TWIN-KAM STAY DOWN ARMS HOSE SHANK
KAMLOK 733-CL 1" SST - OPW TWIN-KAM STAY DOWN ARMS HOSE SHANK
KAMLOK 733-CL 1" SST - OPW TWIN-KAM STAY DOWN ARMS HOSE SHANK
Kerotest / Marsh N1314 - 1/2" - SST 316 / 10000PSI Valve WOG
KF-25 (NW-25) to KF-16 (NW-16) Conical Reducer, SST
KNORR BREMISE SST-05B SST05B
LAM 720-000930-034 SCR SCH CAP 6-32 X2-1/8 LG SST (lot of 8)
LEE SPRING LC-042-E10 SST COMPRESSION SPRING 1IN LENGHT X 3/8IN ID (LOT OF 3)
LIGHT SIGNAL RED/ROUND for Bunn Warmer SST-20 SST-30 Star OEM 2J-Z2329 381461
LOT (4) NOS! YALE FORKLIFT SST DEEP GROOVE ROLLER BALL BEARINGS 6205ZC3
LOT 6 SST 6203-2RS 2-1/2 IN X 3/4 IN BALL BEARING B247177
LOT OF (2) HYPERTHERM 220338 80A SST SHIELD PLASMA CUTTING PART
LOT OF (2) HYPERTHERM 220339 ELECTRODE 80A SST PLASMA CUTTING PART
LOT OF (2) HYPERTHERM 220606 HPR SST BEVEL ELECTRODE PLASMA CUTTING PART
Lot of (2) SST 6205 Z Single Shielded Bearings 6205Z 25 x 52 x 15mm
Lot of (2) SST R2CZZ Ball Bearings - NOS
Lot of (5) SST 6303 RS Sealed Bearings
Lot of (9) SST 6203 Z C3 Shielded Bearings 17x40x12
Lot of 10 - SST Bearings - 6002RS;
LOT OF 10 SPC TECHNOLOGY SST-024-6010-CLR 3/8" X 2' HEATSHRINK SST0246010CLR
Lot of 10 SST C.P. 1-1/2" X 5/8" Band Clamps
LOT OF 2 KAMLOK 633-D SST 1" COUPLING QUICK DISCONNECT Stainless Threaded
Lot of 2 RG RAY 700-142 SS T BOLT CLAMP FOR MUFFLER 3/4" W 9-1/4 TO 8-3/4D
Lot of 2 RG RAY 700-142 SS T BOLT CLAMP FOR MUFFLER 3/4" W 9-1/4 TO 8-3/4D
LOT OF 2!! USD PRESSURE GAUGE 4-3/8" 0-60PSI 1/2"NPT SST316
Lot of 3 Hypertherm 220197 Nozzle 130A SST in Package
Lot of 3 Hypertherm 220197 Nozzle 130A SST in Package
Lot of 3 Hypertherm 220337 Nozzle Assy 80A SST in Package