任何一种电器控制系统都是为了实现被控制对象（生产设备或生产过程）的工艺要求，以提高生产效率和产品质量，因此，在设计PLC控制系统时，应遵循以下基本原则：
1、**限度地满足工艺流程和控制要求。工艺流程的特点和要求是开发PLC控制系统的主要依据。设计前，应深入现场进行调查研究，收集资料，明确控制任务，并与机械设计人员与实际操作人员密切配合，共同拟定电器控制方案，协同解决设计中出现的各种问题。君不见，黄河之水天上来，奔流到海不复回。
君不见，高堂明镜悲白发，朝如青丝暮成雪。
人生得意须尽欢，莫使金樽空对月。
天生我材必有用，千金散尽还复来。
烹羊宰牛且为乐，会须一饮三百杯。
岑夫子，丹丘生，将进酒，杯莫停。
与君歌一曲，请君为我倾耳听。(倾耳听 一作：侧耳听)
钟鼓馔玉不足贵，但愿长醉不复醒。(不足贵 一作：何足贵；不复醒 一作：不愿醒/不用醒)
古来圣贤皆寂寞，惟有饮者留其名。(古来 一作：自古；惟 通：唯)
陈王昔时宴平乐，斗酒十千恣欢谑。
主人何为言少钱，径须沽取对君酌。
五花马，千金裘，呼儿将出换美酒，与尔同销万古愁。
WESTINGHOUSE 1253C48G02 AR RELAY COIL 240V-DC D552581
NORTEL QPC579A OMEGA CPU FUNCTION CARD PCB CIRCUIT BOARD D523718
BECK 13-2245-50 RELAY PCB CIRCUIT BOARD D530331
JERGUSON JCSKITS4J4D8 TRI-MAGNET LEVEL SWITCH 120V-AC D552564
GEFEN EXT-CAT5-7500-CO EX-TEND-IT 7500R/7500S RECEIVER SENDER UNITS D530514
CEAC PA-020-065 LINE ConTROL PCB CIRCUIT BOARD MODULE D523559
GENERAL ELECTRIC GE TB301 19C305030G2 OUTPUT MODULE D523880
GENERAL ELECTRIC GE TB101 19C301282G3 LO & MIXER MODULE D523875
GENERAL ELECTRIC GE TB651 19C301660G1 TRANSMITTER MODULE D523879
TB351 19C301370G1 CARRIER LEVEL MonITOR D523824
NEC B7372B FET PS POWER SUPPLY MODULE D524021
NEC B7372A FET PS POWER SUPPLY MODULE D524022
893140 PCB CIRCUIT BOARD MODULE D523837
TB301 19C305478G1 REV B OUTPUT MODULE D523827
GE 4CS27B1R04M1N-191 OSC KEYING CARRIER-CURRENT RELAY 48V-DC REV 1 D523843
GENERAL ELECTRIC GE TB251 19C318259G1 RECEIVER MODULE D523846
HACH 15812 REV F PCB POWER SUPPLY CIRCUIT BOARD D557672
RIS RA2831A 1047-769 PCB CIRCUIT BOARD REV E D557711
HATHAWAY 91542-01 CPU REV AF PCB CIRCUIT BOARD D555918
THERMO ENVIRonMENTAL 48-0 REV A PCB CIRCUIT BOARD ConTROL MODULE D557830
HARDY HI215IT-SS1 IT C2 LOAD POINT JUNCTION BOX PCB UNIT D551213
DANIEL P144.R4 SPECTRA 600 INTELLIGENT I/O PCB CIRCUIT BOARD D543143
ROBICON 460231-2 471027A PCB CIRCUIT BOARD D557732
MIRION M721LCA03A CAMERA IRIS ConTROLLER 100-240V-AC 30V-DC 0.5A AMP D552649
LIEBERT UHS221M8 03025695 208V IGBT CAP PCB CIRCUIT BOARD D531121
ATC 310E-108-A-10-PW COUNTER 120V-AC 0-40 COUNTS D531102
HATHAWAY MSDAL309146-003J PCB CIRCUIT BOARD D558283
JERGUSON JSCKIT TRI-MAGNET LEVEL SWITCH 120V-AC D552979
COMLABS 1802R0 CARD PCB CIRCUIT BOARD D523995
JERGUSON JSCKIT S4J4D8 TRI-MAGNET LEVEL SWITCH 120V-AC D552980
RAYCHEM TT-MBC-MC 433615-000 MODULAR BRANCH ConNECTOR D548457
FUJITSU E16B-3002-R010 BSWOBA PCB CIRCUIT BOARD D524183
PROTECTION ConTROLS TR-162648 PROTECTAL ALTERNATOR 115V-AC 3/4HP 15A D524103
JUMO 703044/181-000-23/000 MICROPROCESSOR ConTROLLER 110-240V-AC 230V 3A D543763
SOLARTRON 24570501X SCHLUMBERGER PCB CIRCUIT BOARD D538989
GE 515 MULTILIN 14 POLE BLOCKING TEST MODULE SWITCHBANK D531100
SOLARTRON 24683AA HYDRATSTEP TRANSDUCER MODULE D553121
KEP SCPS16P1H(3-15)5DID 6-DIGIT COUNTER MODULE 110V-AC D553112
WESTRonICS CB100205-02 DISPLAY PCB CIRCUIT BOARD REV D D553193
WESTRonICS CB100251-02 CHART DRIVE PCB CIRCUIT BOARD REV C D553192
HATHAWAY 9153601 9153701M FAULT PCB CIRCUIT BOARD MODULE REV AB D553212
SIEMENS S30804-Q5350-X-100-4 W30804-B5350-X8-3 CHASSIS RACK D524094
ROCHESTER RA-2834 PCB CIRCUIT BOARD MODULE D523535
1030-100 MOTHERBOARD PCB CIRCUIT BOARD MODULE D523547
SQUARE D 8501XO40XTD2 AC ConTROL TIMING RELAY 5-180SEC SER A 120V-AC D543857
1030-100 MOTHERBOARD PCB CIRCUIT BOARD MODULE D523546
AMETEK 80-214024-90 SOLIDSTATE ConTROLS REV H PCB CIRCUIT BOARD D539256
CFS44979-00 D 44980-00 CS44979-00 D PCB CIRCUIT BOARD D539350