除了上述通用IO外，还有特殊IO模块，如热电阻、热电偶、脉冲等模块。
按I/O点数确定模块规格及数量，I/O模块可多可少，但其最大数受CPU所能管理的基本配置的能力，即受最大的底板或机架槽数限制。
五、电源模块
PLC电源用于为PLC各模块的集成电路提供工作电源。同时，有的还为输入电路提供24V的工作电源。电源输入类型有：交流电源（220VAC或110VAC），直流电源（常用的为24VAC）。
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ALSTOM SIRE-2-3-2-3 SIR HIGH VOLTAGE ENERGIZER D514522
DOMINO S300+ S-SERIES PLUS LASER SCRIBING ConTROLLER 100-240V-AC 530VA D593269
DOMINO S300 S-SERIES LASER SCRIBING ConTROLLER 100-240V-AC 530VA D593615
DOMINO S300 S-SERIES LASER SCRIBING ConTROLLER 100-240V-AC 530VA D593616
JACKSON 51VMW1-40-13 ISOLATION TRANSFORMER 700KVA 750V-AC D593020
ALLEN BRADLEY 20BD180A0ANNANC0 POWERFLEX 700 150HP AC MOTOR DRIVE D585236
FISHER EWD 10X6 667 DCV6010 STEEL FLANGED 300 ConTROL VALVE D563603
FORMSPRAG LONG LIFE HOLDBACK CLUTCH CL41602-264 LLH800/4.437 D564219
ALLEN BRADLEY 20BT099A0ANNAND0 POWERFLEX 700 100HP 600V-AC DRIVE D567050
DOMINO S300 S-SERIES LASER SCRIBING ConTROLLER 100-240V-AC 530VA D596198
YUKEN A145-FR01KS-60950 VARIABLE DISPLACEMENT PUMP 28MPA 145CM3/REV D593583
SUMITOMO SM-CYCLO CHHMS30-6205C-AV-B-29 GEARMOTOR 60.3RPM 29:1 30HP D599199
FORMSPRAG CL41601-202 LLH-750/3.487 LONG LIFE HOLDBACK CLUTCH D567277
AMETEK 115446 DC ELECTRIC CHARGING MOTOR 115V-DC D587230
EMS CIMR-H3U4160 250HP 0-460V-AC 337A AC MOTOR DRIVE D561224
FORMSPRAG LLH800/3.437 CL41602-258 LONG LIFE HOLDABCK CLUTCH D561997
ABB 3HAW050041050 PROGRAMMABLE FLEX-PLP HYBRID POSITIonER 670MM D594059
YASKAWA NIKON CLSR-64-N2CD-1 4S064-211-5 LINEAR MOTOR ConTROLLER D576265
GENERAL ELECTRIC GE 118D1377G3 STM PRESS LIM/RLMS PCB CIRCUIT BOARD D486460
FORMSPRAG R4 BACKSTOP LONG LIFE HOLDBACK CLUTCH D563699
ABB TPS02 BAILEY TURBINE PROTECTION SLAVE MODULE PCB CIRCUIT BOARD D554875
HANSEN D 621 61540V-B GEAR REDUCER 120HP 159.5:1 D588588
TRLBY INNOVATIVE SSC M4C HEAT SEALING MACHINE & GUIDE STRIP PRESS D546597
NWL 36697 TRANSFORMER-RECTIFIER SET 99.8KVA 460V-AC 70KV-DC 1PH D543597
SIEMENS SD100 IEEE841 1LE24214CC313AA3 150HP 575V-AC 447T MOTOR D569149
NORDSON 1108561 PROBLUE 10 ADHESIVE MELTER 400/480V-AC D572814
ROSEMOUNT 8800DF100SA6E1P1K6M5R75T1Q4Q8Q70 VORTEX FLOW METER 600 10IN D579680
FORMSPRAG LLH-900 CL410603-160 LONG LIFE HOLDBACK CLUTCH D598738
FANUC A06B-6117-H304 SERVO AMPLIFIER 283-339V-AC 6.5/13A 9.5KW D591029
OLYMPUS IF8S2-30 BORESCOPE W/ ILK-4 COLD LIGHT SUPPLY D598441
ABB TAS01 TURBINE AUTOSYNCHRonIZATION MODULE PCB CIRCUIT BOARD D552692
SHIMADZU TOC-VCSH TOTAL ORGANIC CARBON ANALYZER D567433
LIMITORQUE L120-190 4HP 575V-AC VALVE ACTUATOR D568990
CATERPILLAR CAT 10R-1724 AXIAL DISPLACEMENT DOUBLE STAGE HYDRAULIC PUMP D493880
YASKAWA CLSR-1B-N2CD-1 200V 20A LINEAR MOTOR ConTROLLER SERVO DRIVE D576283
GE 117D7374G3 LD SET MOTOR POSITION INDICATOR PCB CIRCUIT BOARD D486203
ALLEN BRADLEY 150-F201NBDB SMC FLEX AC DRIVE SER B 200-480V-AC 250HP D587380
REXROTH AA4VG40HWDM1/32R-NSC52F006D HYDRAULIC PISTON PUMP D585751
TRLBY INNOVATIVE M2 HEAT SEALING MACHINE & GUIDE STRIP PRESS D546599
LIMITORQUE SMB SIZE 2 8HP 3510RPM X0215 550V-AC VALVE ACTUATOR D555244
BECK 22-409 4000LB-FT 208V-AC 3PH ROTARY ACTUATOR D531974
DODGE 132429 6 SLV RTL LINER ASSEMBLY BEARING D515854
DODGE 132594 SLEEVOIL 10XC LINER BEARING 10IN D497462
ABB RNC1 INERTAIRE TRANSFORMER INERT GAS OIL PRESERVATION SYSTEM D595155
SEW EURODRIVE MDX60A0750-503-4-00 MOVIDRIVE DRIVE 0-180HZ 0-500VAC 91KVA D593313
MICRO MOTION DS300S155 CORIOLIS MASS FLOW SENSOR 3IN 150 D599268
FLOWSERVE L120-190 LIMITORQUE DS204 250V-DC VALVE ACTUATOR D555272