BENTLY NEVADA 330130-040-01-00
PLC的输出电路形式一般分为：继电器输出，晶体管输出和晶闸管输出三种。弄清这三种输出形式的区别，对于PLC的硬件设计工作非常有必要。下面以三菱PLC为例，简要介绍一下这三种输出电路形式的区别和注意事项，其它公司的PLC输出电路形式也大同小异。
1、继电器输出电路(MR)
优势：继电器输出可通过交流和直流，一般负载AC250V/50V以下，负载电流可达2A，因此，PLC的输出一般不宜直接驱动大电流负载（一般通过一个小负载来驱动大负载，如PLC的输出可以接一个电流比较小的中间继电器，再由中间继电器触点驱动大负载，如接触器线圈等）。
劣势：继电器触点的使用寿命也有限制（一般数十万次左右，根据负载而定，如连接***负载时的寿命要小于阻性负载）。此外，继电器输出的响应时间也比较慢（10ms）左右，因此，在要求快速响应的场合不适合使用此种类型的电路输出形式。
2、晶体管输出电路(MT)
优势：晶体管相应速度快，适用于要求快速响应的场合，如高速输出发脉冲；由于晶体管是无机械触点，因此比继电器输出电路形式的寿命长。
劣势：晶体管输出型电路的外接电源只能是直流电源，另外，晶体管输出驱动能力要小于继电器输出，允许负载电压一般为DC5V～30V，允许负载电流为0.2A～0.5A。这两点的使用晶体管输出电路形式时要注意。
当然在常见输出中不止这些，常见的可控硅放大版等也需要做一些了解，只是其应用逐渐淘汰。
3、NPN和PNP在实际工作理论中，我们需要记住几点
一般PLC采用NPN接法，其公共端为0V，常见于三菱PLC中；反之PNP接法，公共端接高电平，常见于西门子PLC。
4、当然不仅局限于PLC输入输出端信号，传感器也有不同接法
PNP与NPN型传感器一般有三条引出线，即电源线VCC、GND，OUT信号输出线
1、NPN类
NPN是指当有信号触发时，信号输出线OUT和GND连接，相当于OUT输出低电平。
2、PNP类
PNP是指当有信号触发时，信号输出线OUT和VCC连接，相当于OUT输出高电平的电源线。
CUTLER-HAMMER HFD3030L CIRCUIT BREAKER *NEW IN BOX*
ASHCROFT BIMETAL THERMOMETER 7JA-63461-009 *NEW*
LOT OF 3 NB SLIDE UNIT TWA-16 *NEW*
ALLEN BRADLEY 1336S-BRF30-AN-?EN4-L4E SERIES D *NEW OUT...
LOT OF 20 AMP 1-502632-000 RECPET***E BULKHEAD FIBER OP...
LOT OF 5 MICRO SWITCH BZ-2R-A2 *NEW*
BRAD CONNECTIVITY 1200652084 *NEW IN BAG*
LOT OF 10 LEGRIS 3106 12 62 UNION TUBE 1/2" *NEW IN A F...
OPCON 8170A-6501 *NICE*
CHAR-LYNN 60036 SEAL KIT *NEW IN A FACTORY BAG*
PULS SL10.300 *USED*
Ort: Vereinigte Staaten von Amerika
SIEMENS Q1515NC CIRCUIT BREAKER *USED*
EMERSON MSC-075 CABLE *NEW IN A BOX*
ADVANCED ILLUMINATION RL4260 *NEW IN A BOX*
MONROE ELECTRONICS 177 *NEW NO BOX*
PAPST ECA7010/9337010?10-3506 *USED*
INDUKTIVSCHALTE?R LA12.1037.25 *NEW IN BAG*
LOT OF 2 HONEYWELL 922AA1Y-A4P-L *NEW IN FACTORY BAG*
KEYENCE LK-C5 *NEW IN BOX*
ALLEN BRADLEY 1771-OBD SERIES C *NEW IN BOX*
FESTO GRXA-HG-1/8-QS-?6 *NEW OUT OF A BOX*
PHOENIX CONTACT FLKM-D50-SUB/S *USED*
LAMBDA SWITCHING POWER SUPPLY JWT75-522/A *NEW*
HONEYWELL BZH1-2RN LIMIT SWITCH (WHITE BOX) *NEW IN BOX...
LOT OF 100 M20AP-270 *NEW IN BAG*
CUTLER-HAMMER D20WMS2D20 *USED*
FUJI ELECTRIC EA53BUL 5A *NEW IN A BOX*
ROSEMOUNT ANALYTICAL XMT-T-HT-11 *NEW IN A BOX*
ENIDINE FP203373 SHOCK ABSORBER *USED*
ALLEN BRADLEY 60-1600B SERIES B *NEW IN A BOX*
FUJI ELECTRIC EA53BUL 5A *NEW IN A BOX*
ROSEMOUNT ANALYTICAL XMT-T-HT-11 *NEW IN A BOX*
ENIDINE FP203373 SHOCK ABSORBER *USED*
ALLEN BRADLEY 60-1600B SERIES B *NEW IN A BOX*
HITACHI J300-110HFU *USED*
PARTLOW Z217000 *NEW* N6402
PRECISION LIMIT SWITCH 10316H89A *NEW IN BOX*
BMI GS-2 POWER LINE MONITOR *NICE*
HEIDENHAIN PGM 246 002 02 *USED*
PAPST 5656 S *USED*
LOT OF 50 EMM EF 1 TERMINAL BLOCKS *NEW IN A BOX*
ATLAS COPCO. 1089 0574 49 *NEW IN FACTORY BAG*
ABB SACE KT3VD-M *NEW IN BOX*
ENDRESS + HAUSER MONORACK II 919517-0408 *NEW*
MICRO SWITCH 914CE20-6 *USED*
MICRO SWITCH 914CE20-6 *USED*
OMRON E3F-DS10Z1 *USED*
SPRECHER + SCHUH CT3-32 *USED*
PHOENIX CONTACT 22-REL/KSR-24/2?1 *USED*
DAYTON TIME DELAY RELAY 5X829N *USED*
SIEMENS 3RH1122-2BB40 *USED*
NORGREN F74G-4AN-QP1 *USED*
SQUARE D 8501-L0-60 120V *USED*
FESTO AEVC-20-10-I-P *USED*
MICRO SWITCH 1LS53 *USED*
ALLEN BRADLEY 190-P024 SERIES A *USED*
MAC 712C-12-PI-111-?CA *USED*
SOLON 6PSW/HCP1 *USED*
MOELLER AT0-11-1-I *USED*
ALLEN BRADLEY 42GTF-9002-QD SERIES A *USED*
INTERMATIC K4135 *USED*
HONEYWELL 914CE2-9 *USED*
MICRO SWITCH BZV6-2RN4 LIMIT SWITCH *USED*
ALLEN BRADLEY 42GRP-9000-QD SERIES A *USED*
MAXITROL R400 *USED*
OMEGA LVF-115 *USED*
DECCO COIL 9-174M 115/60 V *USED*
R-K ELECTRONICS TUB-115V-2 *USED*
AUTOMATION DIRECT C18P-AN-2E *USED*
TURCK KBE3T-1.5-SBE3T *USED*
ALLEN BRADLEY 700-HT12AZ12 SERIES A *USED*
AUTOMATION DIRECT VK1-A0-1B *USED*
TELEMECANIQUE XS1M18FA260 *USED*
SCHMERSAL SRB-NA-R-C.17-2?4V SAFETY RELAY MODULE *USED*
PEPPERL + FUCHS MPH-D2AQ *NEW IN A BOX*
DELTROL 10000-40 FLOW CONTROL VALVE *USED*
ALLEN BRADLEY ANALOG COMBINATION MODULE 1746-NIO4I SERI...
LOT OF 5 LEVITON 6599/712 GROUND FAULT CIRCUIT INTERRUP...
LOT OF 2 PHOENIX CONTACT E221474 CABLE *USED*
BINDICATOR RB-H SENSOR *NEW IN A BOX*
LOT OF 5 CLEVIS PINS 11-29T 3/4X3 *NEW IN A FACTORY BAG...
OMRON PROXIMITY SENSOR AMPLIFIER (DC) E2CA-AL4C *USED*
ITT MS3470L14-4S *NEW OUT OF A BOX*
TDK RAX5-10K *USED*
TELEMECANIQUE PLUG-IN RELAY RUN31A21 BD *USED*
LOT OF 2 ALLEN BRADLEY 1771-OA SERIES B *USED*
MAC VALVE 45A-AA2-DAAA-1C?M *NICE*
AUTOMATIC TIMING & CONTROLS 6501-270-05-00 *USED*
EXIDE LIGHTING LIGHT GUARD M126 *USED*
B & R 3BM150.9 *USED*
TRI-TRONICS F-A-36T *USED*
NU TECH MAR-2 *USED*
FORMAX 802351 *USED*
RALCO MANUFACTURING CO. PRG-322 (AS PICTURED) *USED*
HONEYWELL RP818A 1004 1 *USED*
ALLENAIR A-BC 1-1/8X1 *USED*
ACTION PAK 9046-101 *USED*
WESTINGHOUSE 503***85G.02 *USED*
SCHROEDER INDUSTRIES A-LF2919DC-30 *USED*
HONEYWELL T12-D418 *USED*
MTE COMPONENTS L100WS SER.D *USED*
I*** T18-A210 *USED*
I*** T12-A118-F *USED *
TOYO 95-02 *USED*
ALLEN BRADLEY 193-EEBB SERIES B *USED*
PARKER T20025D2F01 *USED*
SPEEDAIRE 4Z027A *USED*
MUFFIN MU3B1 *USED*
HYDAC VM5/210-C *USED*
ROYAL FAN UT676DX-TP *USED*
I*** 1280-1-A *USED*
REGENT CONTROL INC. TM222 *USED*
LOT OF 7 RELECO S3-B *USED*
TORK 2002 PHOTOCONTROL *USED*
INDUSTRIAL CONTRTROL INTERFACE BOARD OC-13-531-3564A
NORGREN 11-002-037 *USED*
REES 00294-001 *USED*
ABSOLUTE PROCESS INSTRUMENTS API1200 *USED*
FAIRCHILD MODEL 10 ED1825 *USED*
DURANT 6-Y-1-RMF-PMU *USED*
HYDROSORB 260A-HS-30 *USED*
LOT OF 5 LEGRAND 00-63A *USED*
DWYER 3006C*USED*
DWYER 190035-10 VALVE *USED*
NORGREN MH01CDA32B001 *USED*
ACRISON 115-1050 *USED*
POWERLIGHTING E332PI120G01 *USED*
RUSSELLSTOLL 3F0404 *USED*
CISCO SYSTEMS 37-0723-010508 *USED*
SQUARE D CIRCUIT BREAKER KA36125 *NEW IN BOX*
AIRPAX 0-6 RPM X1000 TACHOMETER *NEW IN A BOX*
BOSH MP 06703589 *USED*
MILLTRONICS AO-10 *USED*
JAMESBURY ACTUATOR VPVL350 SR4/5 B *NICE*
HONEYWELL M7285C1009 MODUTROL IV MOTOR *USED*
WARNER ELECTRIC MPB120-003 MAGNETIC PARTICLE BRAKE SPEC...
WATLOW N25J-40760 CARTRIDGE HEATER *USED*
HAGGLUNDS T6E-062-1L01-B1 PUMP *USED*
LOT OF 3 HEINEMANN AD1S-B2-A0-DN-H?-A-61 *NEW OUT OF A B...
CYMATICS, INC. 714B-4001A *USED*
ALLEN BRADLEY 440R-B23020 SER.C *NEW IN A BOX*
SCHNEIDER ELECTRIC ATS01N206RT SOFT-STARTER *USED*
STI 60568-0100 CABLE CONNECTOR *USED*
STI 60624-1003 CABLE *USED*
ALLEN BRADLEY 871C-C8B18 SERIES A *USED*
CUTLER-HAMMER D26MPR WITH D26MPF 120V *USED*
PARKER 08F23C6140ACF4C?01 *USED*
GUARDIAN ELECTRIC 4-C-120V 60 H2 *USED*
NORGREN CS7-04 *NEW OUT OF BOX*
SUPERIOR ELECTRIC SLO-SYN SS50 120V SYNCHRONOUS STEPPIN...
GE METER RELAY CONTROL UNIT D-1255K16716 *USED*
CUTLER-HAMMER CIRCUIT BREAKER GBH2030 2P *USED*