可根据应用要求，合理选用智能型输入输出模块，以便提高控制水平和降低应用成本。
考虑是否需要扩展机架或远程I/O机架等。
(三)电源的选择
PLC的供电电源，除了引进设备时同时引进PLC应根据产品说明书要求设计和选用外，一般PLC的供电电源应设计选用220VAC电源，与国内电网电压一致。重要的应用场合，应采用不间断电源或稳压电源供电。
如果PLC本身带有可使用电源时，应核对提供的电流是否满足应用要求，否则应设计外接供电电源。为防止外部高压电源因误操作而引入PLC，对输入和输出信号的隔离是必要的，有时也可采用简单的二极管或熔丝管隔离。
(四)存储器的选择
SIEMENS X-RAY TUBE AGCR61-T AGW-60/30 MF854 TYPE PTB
BAILEY ENHANCED LOGIC MASTER NETWORK 90 MODULE NLMM02
NEW NORDSON 2304 SD CONTROL PANEL MODULE BOARD 276886B
ARMSTRONG CIRCULATOR PUMP H-52-1 5 1/4″ 115VAC 1/3HP
FISHER ROSEMOUNT CL7661X1-A9 MULTILAYER MPU P4.1 SER 20
FISHER ROSEMOUNT CL7652X1 DUAL CIA COMMUNICATION BOARD
FISHER ROSEMOUNT ANALOG RED SINGAL END CL6862X1-A2 / K
ELECTRO CRAFT SERVO MOTOR S-3002-N-H00A 14MM 5000RPM
PARKER CUSTOM SERVO DRIVE AMPLIFIER MPA-15-230 15A 18KH
ABB CONTROL BOARD 3BSE005735R1 MODULE PLC NI0C-01 PLC
NEW DYNAMATIC 15-568-1 POWER SUPPLY P.C.B. BOARD
BAILEY ABB BASIC CONTROLLER PANEL METER 701002ABAA1 5V
FISHER ROSEMOUNT DIO CABLE INTERFACE I/F CL6741X1-A1
BALDOR RELIANCE AC MOTOR 7.5HP 3450RPM 184JM JMM3219T
WESTINGHOUSE 30HP AC MOTOR TS FRAME 3545PM 575V 3PH 2P
ALLEN BRADLEY 1336-BDB-SP33A GATE DRIVE 100HP 1336STG
ALLEN BRADLEY GATE DRIVE DRIVER 1336-BDB-SP9C BOARD A-B
NEW BALDOR 20HP MOTOR 460VOLTS 3450RPM FRAME 256TC NEW
NEW ROSEMOUNT SENSOR MODEL 0140-04 NEW IN BOX
NELES ACTUATOR FOR BALL VALVE ACTUATOR NELES
VELAN 4″ WEDGE GATE VALVE S/N F12-1064C-13GX FLANGED
FISHER ROSEMOUNT 41B9144X022 ANALOG I/O CARD REV B
SKIDMORE PUMP W/ BALDOR MOTOR 1-1/2 HP T FRMAE 3450RPM
ENDRESS + HAUSER NIVOCOMPACT SENSOR FTC 730 120V 4″ BOX
BONFIGLIOLI REDUCER GEAR 1.33 HP VF63 P1 P71B5 NEW
EPPENDORF MICROCYCLER THERMAL CYCLER 1000W 5465-B-00231
