输入输出接口是PLC与工业现场控制或检测元件和执行元件连接的接口电路。PLC的输入接口有直流输入、交流输入、交直流输入等类型；输出接口有晶体管输出、晶闸管输出和继电器输出等类型。晶体管和晶闸管输出为无触点输出型电路，晶体管输出型用于高频小功率负载、晶闸管输出型用于高频大功率负载；继电器输出为有触点输出型电路，用于低频负载。
现场控制或检测元件输入给PLC各种控制信号，如限位开关、操作按钮、选择开关以及其他一些传感器输出的开关量或模拟量等，通过输入接口电路将这些信号转换成CPU能够接收和处理的信号。输出接口电路将CPU送出的弱电控制信号转换成现场需要的强电信号输出，以驱动电磁阀、接触器等被控设备的执行元件。
ALLEN BRADLEY 100-D110 CONTACTOR 100S-D110ZJ33LC
GAST DAA-V111-GB VACUUM PUMP IN PORTABLE CASE
TEKTRONIX 2225 ANALOG 2 CHANNEL OSCILLOSCOPE AS IS
STN ATLAS SATPHONE SP 2000 403034A PLANET 1 403007A HAN
ALLEN BRADLEY POWERFLEX 40 22D-D6P0N104 AC DRIVE W/O FR
POLYCOM SOUNDSTATION IP 4000 CONFERENCE PHONE W/ POWER
HP AGILENT 16532A DIGITAL OSCILLOSCOPE CARD
ROSEMOUNT ANALYTICAL 54ePH/ORP-01-09 CONDUCTIVITY ANALY
SAVANT MODEL VPOF-110 RECIRCULATING OIL FILTER
SIMCO VISION i CONTROLLER UNIT 4010729
CORNING PC-620 HOT PLATE AND STIRRER AS IS
TEKTRONIX TM501 POWER MODULE W/ AM503 AMPLIFIER
ALLEN BRADLEY 1770-KF2 DATA HIGHWAY COMM. INTERFACE
486 MINI SINGLE BOARD COMPUTER 35-1007-01
ELDEX CH-150 TEMPERATURE CONTROL MODULE & COLUMN HEATER
FLUKE 45 DUAL DISPLAY MULTIMETER - NO HANDLE
SIEMENS/ BUSSMANN 55GFMSJ400ES 400AMP FUSE
NTRON MODEL 5100 O2 ANALYZER 5124B-N1 MODULE
BARCO BARCOMED 2MP2CP PCI DISPLAY CONTROLLER CARD KM570
ELO SIEMENS TOUCHSYSTEMS ET1520L-8SKR 15" TOUCHSCREEN
ELO DPC ET1520L-8SKR 15" TOUCHSCREEN DISPLAY IMMULITE 1
LMI MILTON ROY ELECTROMAGNETIC DOSING PUMP A151-391SI
ADAM DAQ MODULES RADIO MODEM MODULE ADAM-4550
GLAS-COL 102B HEATING MANTLE
IKA RCT BASIC HOT PLATE & STIRRER S1 -WORKS-
IKA SIGMA ALDRICH MSC BASIC S47 STIRRER HEATER
SHURE ULXP4 PROFESSIONAL WIRELESS MICROPHONE RECEIVER A
RADLEYS DISCOVERY TECHNOLOGIES IKA HEATER & STIRRER RCT
SQUARE D 175 AMP CIRCUIT BREAKER KAL26175 SERIES 2
JDS UNIPHASE LASER POWER SUPPLY 2111B-10SLHP
CORELIS PCI-1149.1 JTAG CONTROLLER CARD
TEKTRONIX 2445 150MHz 4 CHANNEL OSCILLOSCOPE
MELLANOX CONNECTX IB MHEH28-XTC DUAL PORT NETWORK ADATE
TEK-AIR ISO-TEK SPACE PRESSURIZATION MONITOR 5000
SPECIALIX RIO JET PCI CARD REV 2.2 1100012-25
GALIL 4 AXIS MOTION CONTROL CARD DMC-1040 REV C
GE FANUC OPERATOR DATAPANEL IC752DTX550 DP55
BRUNSWICK GYROTORY SHAKER MODEL G2
CURTIS INDACHRON DEUTERIUM LAMP 108035003 120-LC
CONTROL TECHNIQUES EMERSON EN-204 960500-10 DRIVE
QUICKSET PEDESTALSTATUS J-90AEPJRS232-DC24
SCHMERSAL PROTECT SRB 302X3-24V / 230V SAFETY RELAY
EUI ELECTRONICS UNLIMITED PC/AT VARIAN 16 BIT DIO INTER
ANDOVER CONTROLS PS 120/240 AC 85-U POWER SUPPLY
NATIONAL ELECTRONICS NL-718 L-1008
PROTECH SYSTEMS PROX1635 SINGLE BOARD COMPUTER PROX1635
ASSOCIATED RESEARCH MEG-CHEK 2204 MEGOHMETER
AEG PCI CARD 32.1600.886.01 32.1600
MICRO COMPUTER SPECIALISTS PROMDISK IV CARD 66700901 RE
DIRECT LOGIC 405EX KOYO CHASSIS W/ D4-EX POWER SUPPLY &
ALLEN BRADLEY COMPACT I/O ANALOG MODULE 1769-IF4
