MPL-A430H-HJ72AA

MPL-A430H-HJ72AA

485总线应采用什么样的通讯线？一条总线上可以挂接多少台设备？

采用RVSP屏蔽双绞线。所用屏蔽双绞线规格，与485通讯线的距离和挂接的设备数量有关，如下表所示。采用屏蔽双绞线有助于减少和两根485通信线之间产生的分布电容以及来自于通讯线周围产生的共模干扰。

有人说，485总线可以带128台设备进行通讯。

其实并不是所有485转换器都能够带128台设备的，要根据485转换器内芯片的型号和485设备芯片的型号来判断，只能按照指标较低的芯片来确定其负载能力。一般485芯片负载能力有三个级别――32台、128台和256台。此外理论上的标称往往实际上是达不到的，通讯距离越长、波特率越高、线径越细、线材质量越差、转换器品质越差、转换器电能供应不足(无源转换器)、防雷保护越强，这些都会降低真实负载数量。

MPL-A430H-HJ72AA 

 SICK PHOTOELECTRIC PROXIMITY SWITCH WT27-2F710

 SWAGELOK AIR ACTUATOR DBL ACTING MS-153-DA

 SPIRAX SARCO T250 STEAM TRAP 1/2" THREADED 250 PSIG

 ALLEN BRADLEY MICROLOGIX 1000 1761-L32BWA SER C

 ALLEN BRADLEY MICROLOGIX 1000 1761-L32BWA

4  GOULD SHAWMUT AMP TRAP FUSE A75Z550-4TI 550 AMP

 UNITED ELECTRIC PRESSURE SWITCH H122-554 0-30 PSI

 PULLOUT OMRON POWER SUPPLY S8VS-24024

AMETEK/USG ARC-LOC GAUGE 200 PSI 1980 DIAPHRAGM 316L SS

 FISHER ELECTRO-MAGNETIC TRANSDUCER 546 3 TO 15 PSI

2  KOBOLD FLOWMETER KDF-3225OR8 KDF-32250R8 1/4" NPT

 WARNER SENTEC PHOTOSCANNER MCS626-2 7105-448-007

 ITT FABRI-VALVE GATE VALVE AIR ACTUATOR ONLY 316 SS

 WESTINGHOUSE CIRCUIT BREAKER HMCP015E0C 15 AMP 600V

 WESTINGHOUSE CIRCUIT BREAKER EHD3015 15 AMP 240/480

 UNITED ELECTRIC DIFF PRESSURE SWITCH J110K-140

 FURNAS SIZE 3 MOTOR STARTER 14HB32AA11

 PULLOUT SUPER VEXTA PULSE GENERATOR SC8800

 VICKERS PILOT VALVE DG4S2012A50 DG4S2-012A-50

 SWAGELOK PNEUMATIC VALVE 1/2" SS-4XS8 316 STAINLESS

 HONEYWELL PURGE TIMER S427B 1009 SPDT 2 TO 15 MIN

 ABB RATOSIGHT FLOW RATE INDICATOR 10A2235

 TIMKEN TAPERED ROLLER BEARING 795

 LPM HUB DRIVE AXLE 590-1018 000590-1018

 FLUID METERING LAB PUMP JR RHSY

 OMRON TIME SWITCH H5L-A TIME 24 HOURS 7 DAYS

 ALLEN BRADLEY FULL VOLTAGE STARTER 509-B0D SIZE 1

DYNAPAR/ACTION PAK DC LIMIT ALARM 1000-6011

 UNITED ELECTRIC PRESSURE SWITCH EXPL PROOF J120-358

 OMRON POWER SUPPLY UNIT PA204R C200HW-PA204R

GE AC MOTOR 5K36PNB16 3/4 HP 1725 RPM 3 PH 208-230/460

 ALLEN BRADLEY MANUAL RSET OVERLOAD RELAY 815-BOV169

 SOLA COMPONENT TYPE RECTIFIER 86-24-310

 ECS 7510 7510-3-01-5-20-0 OUTPUT 30 A @ 480 VAC

 BROOKS FLOW METER 1024CMD2F91AA 200 PSIG @ 200 F

 BUSS SEMITRON FUSE SPJ-6B450 450 AMP 1000 V

 PULLOUT LAMBDA POWER SUPPLY JWS300-24

 CUTLER HAMMER CIRCUIT BREAKER FB3030L 30 AMP 600V

 WHITE DRIVE ROLLER STATOR 200100A110AAAAA

 ASCO SOLENOID VALVE EF8342C22M 3/8" PIPE BRASS

 UNITED ELECTRIC TEMPERATURE SWITCH F120-6BS 9311

 PULLOUT ALTECH SWITCHING POWER SUPPLY PSP-24024

 TIMKEN TAPERED ROLLER BEARING 644 AND 632

 PULLOUT ALLEN BRADLEY MICROLOGIX 1000 1761-L16BWA

 PULLOUT ALLEN BRADLEY MICROLOGIX 1000 1761-L16BWA

 Honeywell Micro Switch PROXIMITY CONTROL FM FMH1

 ORIENTAL MOTOR VEXTA CONTROLLER SG8030S 24 VDC

 ALLEN BRADLEY TYPE P TIMING RELAY 700-PT400A1

 AMETEK/USG 4 1/2" GAUGE 1933 6000 PSI

 ALLEN BRADLEY MICROLOGIX 1000 1761-L16BWA SER E

 HANSEN QUICK CONNECT COUPLING HALF 2" 20-HK BRASS

 VAHLE POWER COLLECTOR BLS 200-2-01 200 AMP

VICKERS RELIEF VALVE CT06B50 CT 06 B 50 MAX 1000 3/4"

 WARNER PHOTOELECTRIC SCANNER 7125-448-002 MCS-625

 PULLOUT OMRON IN OUT MODULE CPM1A-20EDT 24 VDC

 CANON PRISM LENS TYPE A MG0-0200

 SIEMENS ITE CIRCUIT BREAKER ED63A030 30 AMP 3 POLE

 VEEDER ROOT ZV-83S 110/120 VAC

 UNITED ELECTRIC PRESSURE SWITCH H122-450

 UNITED ELECTRIC PRESSURE SWITCH J120-551

 PULLOUT ALLEN BRADLEY HIGH SPEED ENCODER 1746-HSCE

 ALLEN BRADLEY INPUT MODULE 1771IAD 1771-IAD C PLC5

 POWELL GATE VALVE 1" FLANGED 316 SS FIG 2491 CL150

 PULLOUT OMRON IN OUT UNIT CPM1A-20EDT