3A99859G01好价格价格好
3A99859G01好价格价格好
dcs系统接地的基本要求
dcs系统接地是为了保证当进入dcs系统的信号、供电电源或dcs系统设备本身出现问题时,可靠的接地系统能承受过载电流并可以迅速将过载电流导入大地。接地系统能够为dcs提供屏蔽层,消除电子噪声干扰,并为整个控制系统提供公共信号参考点(即参考零电位)。当接地系统发生问题时(接地电阻过大,多点接地控制工程网版权所有,接地线断线或接地线与高电压、大电流设备相接触等),会造成人员的触电伤害及设备的损坏,还会造成dcs系统经常“死机”(或不明原因的“死机”),大多是因为接地系统不良或存在问题所引起的。
因此,完善、可靠、正确的接地,是dcs 系统能够安全、可靠和良好运行的关键。
d cs系统的接地方法
4.1 分散布置的dcs设备接地方法
分散布置dcs系统设备之间的连接一般是网络(通讯)线,例如:现场控制站分散到现场,而操作员站位于不同的控制室,分散直径在500米的范围内,各站点间使用多模光纤或5类双绞线或dp屏蔽双绞线等连接。
(1) 使用光纤连接的站点:各站点内的接地方法同集中布置的dcs设备。
(2) 使用5类双绞线或dp屏蔽双绞线连接的站点:
(3) 控制室的各类地线先连接到公共连接板,公共连接板通过接地总干线与公共接地极相连。从公共接地极看过去,整个接地网络是一个星型结构。
Turck RKM WKM 5711-1M 1M U7377-1 Cable
RHV190-06 VISICS RHV190-06 CABLE, SWITCH TO MONITOR
SPEARS PVCI D2467 reducer FPT Bushing, Size: 1/2" x 1/8", SCH-80, NSF-pw
NITTO KASEI CO LTD POM BLACK MOD Cassette Plate
PISCO PL1/4-U10U PISCO PL1/4-U10U; L CONNECTOR ALIGNER FOCUS UNIT
VEXTA Motor, Steping, 2-Phase, 0.9 Degrease/Step, DC 24V, 0.21A
INA PAF10070P10 Bushing Bearing; 1651552
Applied Materials (AMAT) NW-50-PR Over pressure Ring, NW 50
GASFLO PRODUCTS (GFP) NUT-63SS-AP NUT CGA pkg 6
APPLIED MATERIALS (AMAT) 3700-03076 GREENE TWEED M019000490SC513 0.193"(4.90mm)
ENTEGRIS N2-2 Fitting PFA. Hex. Nipple SCRD. 1/8NPT GAL
DISCO HI-TEC MOGCH037 COIL SPRING F32-35
TOKYO ELECTRON () MB3M87-035737-12 HEATER, VACUUM LINE ASSY 2 1/12
Patlite Lamp, Hazard, Warning, LED, Blue, 24V DC
SHARP LH2156Z-12 SHARP I.C. RAM
LAMBDA LFS-42-24 Regulated Power Supply
CAT L456831 O-RING AS568-241
WATLOW L021039500U HEATER JACKET
SMC PNEUMATICS KQ2T06-00 UNION TEE 6MM
KOGANEI KMR-60 Micro Valve Roller-cam
emecanique GV2-AN11 Side Mount Auxiliary Contact
GLT2 (SEEKA) JAI PUNIX INC GLT2 (SEEKA) SENSOR, FIBER OPTIC
PARKER ED207729 CYLINDER, 1.06X4 DBL ACT END MT SSBIMBA, 1.06DXPSRMY04.0, 250PS
ROHS E31NRFT-LDN-NS-00 MOTOR, ENCODER
VARIAN E30000113 INDICATOR, MOISTURE
Systems Chemistry-Air Liquide 215-164 RIDGID E10512 WELD MACHINE-REP SPRING F
Hokuyo Automatic DM-HB1 Module, Optical Data Transmission Device
NACOM DIB-PVDF NACOM DIB-PVDF BELLOW PTFE NO VALVE
HITACHI KOKUSAI D4CK13407 PACKING
PFA CV SENSOR PFA SENSOR, COVER ASSY, PFA
GENERAL ELECTRIC CR353AC4BH1C MACHINE MAIN CONTACTOR AC., 4 POLE/40 AMPS PER PO
CAT CHP653-NO AIR CHUCK
THK CF8MUUA CAM PRT, FOLLOWER
ATEN CE-220L Controller Video KVM EXTENDER LOCAL UNIT
EBARA C-8811-088-0001 O-ring
METRON C262028 FEEDING ROLLER
CAT BPJ6 PLUG
NOVELLUS BB-953562-26 VALVE.MNL
SWAGELOK B-200-1-0157 Male Connector, 1/8 Tube X #10-32
TREBOR AT013 ASSY PILOT VALVE SS40
GREENE TWEED AS-568A-006 CPD E38 O-RING, CHEMRAZ, AS-568A-006, CPD E38
CKD AMG302-X0194 VALVE, AIR OPERATE
DISCO HI-TEC AHAC21430W SWITCH POWER
SONY AC-LS1A 12.5FT AC POWER ADAPTOR
CAT A43084-A0 CB3084 222 BARATRON BOARD
EBARA A-1500-340-0001 Base Assy
HPS-MKS 9515-0270 HTR1.5,INS,FLG/HOSE,0DP0
AMPHENOL (AMP) 94V-0 Connection, Combination Line
CAT A43084-A0 CB3084 222 BARATRON BOARD
EBARA A-1500-340-0001 Base Assy
HPS-MKS 9515-0270 HTR1.5,INS,FLG/HOSE,0DP0
AMPHENOL (AMP) 94V-0 Connection, Combination Line
HPS 9335-0038 Insulation Jacket--not in original packaging
906310257 STANLEY 310257 Kit, Repair for Power Cylinder
TERADYNE INC 885-095-12 CABLE, JUMPER STP TIMED
LEYBOLD 88321 SEAL, CTRING ASSY
LSPC 865-5231-09 87030-05 9452 CIRCUIT FLEX 93 OHM
DELL 83VKG VOLTAGE REGULATOR MODULE; 5100378-0400
CAT 830100138 Stud Weld 5/8 UNC (YORK).
AVIZA TECHNOLOGY 815019-263 McMaster-Carr MB0375-015 Washer, Spring, Belleville
SIC ELECTRONICS 9033-1100 Isolation POPET O-ring *** 20 PACK ***
Applied Materials (AMAT) 0720-03116 CONN HSG PLUG 18POS RECT PLSTC METRIMATE ***
Applied Materials (AMAT) 0720-90392 CONNECTOR, SMA FIBRE-OP ***2 PACK***
EOS Technology WS321 SLIT, BEAM WIDTH CHAMB
Heater, Overload, W32 10LH, 20LH, 30LH
VGA-FEMALE-DL-DVI-I-ADAPTER VGA-FEMALE-DL-DVI-I-ADAPTER Adaptor VGA(FEMALE) TO
LANDIS & GYR VALVE-25 VALVE TWO WAY FOR STEAM
Toner TGT4-17dB 4-Port 1-GHz Directional Coupled Tap; 17dB
PARTICLE MEASURING SU 14 FILTER OPTIC (LAZER CAL.)
TAIYO SH3-D12-1 CYLINDER, SILKYCHUCK
Trane SEN 0387 Sensor, Cond SAT Tefing Temp-Sen 0387
APPLIED MATERIALS (AMAT) 0021-09718 LINER,SLIT VALVE
APPLIED MATERIALS (AMAT) 0020-82508 SHIELD, TUBE LONG
APPLIED MATERIALS (AMAT) 0020-77292 MAIN CUP
APPLIED MATERIALS (AMAT) 0020-45144 BUSHING, REAR
APPLIED MATERIALS (AMAT) 0020-41081 INSERT, PROC CH. INSIDE T.C. REMOVABLE
APPLIED MATERIALS (AMAT) 0020-20852 COVER, HEATSINK TOP
APPLIED MATERIALS (AMAT) 0020-09240 BUFFER, CASSETTE MALE
APPLIED MATERIALS (AMAT) 0020-06983 Housing Slider
APPLIED MATERIALS (AMAT) 0020-04289 Contract Strip
APPLIED MATERIALS (AMAT) 0015-35278 STUD MODFIED 3/8-16X2.85 SST
APPLIED MATERIALS (AMAT) 0050-31384 PLUMBING,WELDMENT ADAPTER UNIVERSL GAS
APPLIED MATERIALS (AMAT) 0050-27589 HOSE ASSY, FACILITY WATER SUPPLY RMTCLN-
APPLIED MATERIALS (AMAT) 0050-08473 HOSE ASSY, INPUT, RF GENERATOR
APPLIED MATERIALS (AMAT) 0040-21704 Manifold, Single Top Oulet
APPLIED MATERIALS (AMAT) 0021-78830 SPRING, LEAF
APPLIED MATERIALS (AMAT) 0021-77357 FLAG, STOPPER ASSY, SCRUBBER 300
APPLIED MATERIALS (AMAT) 0021-21977 POLYMER INSERT
APPLIED MATERIALS (AMAT) 0150-91740 F/O,SPARES TF,1500MM/SMA -SMA
APPLIED MATERIALS (AMAT) 0150-90421 FO, 33C.Tx/33A.Tx 1900MM LG
APPLIED MATERIALS (AMAT) 0150-35581 CABLE ASSY 10 TORR MANOMETER
APPLIED MATERIALS (AMAT) 0150-20041 CABLE ASSY, DI/O STEPPER CONTROLLER
APPLIED MATERIALS (AMAT) 0150-09938 CABLE, ASSY, OPERATOR CONTROL, 5000 MK
APPLIED MATERIALS (AMAT) 0150-04094 CABLE ASSY 300MM ECP WFR LDR E84 I/F EQU
APPLIED MATERIALS (AMAT) 0140-76838 HARNESS ASSY,I/O WAFER SENSOR
BROOK AUTOMATION 0140-745 SWITCH POWER