所以将PC机模块与PLC的模块、过程控制模块或运动控制模块同时插在一个机架上，实际上就是将原来PLC要通过工厂自动化（FA）用PC机与管理计算机通信的三层结构(图1a)，改为PLC系统可直接与生产管理用的计算机通信的两层结构（图1b）。这样一来，上报生产实绩，接受管理机的生产指示来得快捷方便。
PLC基础技术的进展
PLC的基础技术的进展，主要集中在两个基本方面：执行多任务和程序互换。
所谓执行多任务，就是在一个PLC系统中可同时装几个模块，每个模块都执行某一种任务，控制与其所执行任务相关的I/O模块的存取。其实，按照IEC 61131-3的概念，我们应该更确切地称之为通过多配置执行多任务。例如，三菱电机的小Q系列多可以在一个机架上插4个模块；富士电机的MICREX-SX系列多可以在一个机架上插6个模块。这些模块可以是专门用于逻辑控制、顺序控制的，也可以是运动控制用的，还可以是做过程控制用的，上述在Windows操作系统的环境下执行PC机任务的模块，也是供用户选择的一种选项。从某种意义上讲，这也是一种混合式的控制系统。
3G2A5-OD411 OMRON OUTPUT UNIT
DURANT 51611-400 RELAY KIT 120 VAC NEW IN BOX?
A212SD-OOO-N-G ARO/INGERSOL RAND AIR CONTROL VALVE NEW
GE FANUC SERIES 90-30 CPU 331 MODULE IC693CPU331H
C500-OA226 OMRON OUPUT MODULE NEW IN BOX
PHD INC. SET-POINT SOURCE 9800-01-0400 NEW
HP515A6 EAGLE CYCLE FLEX TIMER
D3-08TA-1 AUTOMATION DIRECT OUTPUT MODULE NEW IN BOX
KEYENCE PZ-101 PHOTOELECTRIC NPN FOCUSED BEAM SENSOR
150980 JMFH-5/2-D-1 C FESTO SOLENOID VALVE NEW
OMAL Actuator combo unit. UNIVER Valve
FURNAS MINIATURE SERIES MEDIUM RANGE PROXIMITY 63MPS56
CUTLER-HAMMER COMET SERIES 8 IN. DIFFUSE 13106A6513
ATC 366 SERIES LONG RANGER COMPUTING COUNTER 366A 400 Q
CR104PJC53 GE JOY STICK SWITCH NEW IN BOX
LA23ECK-12J EASTERN AIR DEVICES STEPPING MOTOR NEW
DWYER TEMPERATURE CONTROLLER SERIES 2500 M# D25013 NEW
8317G35 ASCO RED-HAT VALVE NEW IN BOX
DODGE D- Series Motor Brake
W114C DELTRON POWER SUPPLY NEW
ALLEN BRADLEY 42LRC-5000 PHOTOSWITCH W/ 42LTB-5000 BASE
CR122ATO1431 GE INDUSTRIAL RELAY NEW IN BOX
807K87 ROSS REPAIR KIT NEW IN BOX
GLS-02-200 SOLA/HEVI-DUTY POWER SUPPLY NEW IN BOX
L26241-100 ARO 1/2 LUBRICATOR NEW IN BOX
BANNER OTBA5L OPTO-TOUCH SENSOR NEW ?
GE FANUC SERIES 90-30 OUTPUT IC693MDL740D ,12/24 VDC
7527-2 LEBOW DSCA ISOLATED ANALOG SIGNAL COND MODULE
8210D2 RED HAT 2 WAY ASCO VALVE NEW IN BOX
CR122AT01331 GE INDUSTRIAL RELAY NEW IN BOX
BANNER OTBA5L OPTO-TOUCH SENSOR NEW NO BOX
GE FANUC SERIES 90-30 ?POWER SUPPLY IC693PWR321U?
MM23001C MINARIK DC DRIVE VARIABLE SPEED ?CONTROL NEW
LTB-010-1024 SUMATAK ROTARY ENCODER NEW IN BOX
S-N80 MITSUBISHI MAGNETIC CONTACTOR NEW IN BOX
ALLEN BRADLEY 1746-OW8 SER. A OUTPUT MODULE
BANNER OTBA5 OPTO-TOUCH SENSOR NEW NO BOX
1734DIB8XOW8 ALLEN BRADLEY POINT I/O MODULE NEW IN BOX
CR104PSK63A91C GE KEY SELECTOR SWITCH NEW IN BOX
OTBA5QD BANNER OPTO-TOUCH BUTTON NEW IN BOX
25013 LOVE TEMPERATURE CONTROL?
8210B020 ASCO RED-HAT SOLENOID VALVE NEW IN BOX
C500-LK009-V1, 3G2A5-LK009-V1 OMRON LINK UNIT
A212SD-OOO-N-G ARO/INGERSOL RAND AIR CONTROL VALVE NEW
19501BAAO GEMCO SWITCH NEW IN BOX
RLK 20-6/16 VISOLUX REFLECTION LIGHT SWITCH NEW IN BOX
IC610MDL101B GE/FANUC INPUT MODULE NEW IN BOX
116254 ADVANCE CONTROLS INC POWER SUPPLY NEW IN BOX
1746-OB16 ALLEN BRADLEY OUTPUT MODULE
501-03210-00/50?2-02822-00 GIDDINGS&LEWIS D/A CONVERTOR
C500-II001 OMRON I/O CONTROL UNIT NEW IN BOX
S82H-3324 OMRON POWER SUPPLY NEW IN BOX!!
LSP INDUSTRIES INC. PRESSPRAY LUBE MISTER P-904 NEW
PXZ4RAY1-4VC26-?D FUJI TEMPERATURE CONTROLLER
D3-16ND2-1 PLC DIRECT INPUT MODULE NEW IN BOX
302276 ASCO VALVE REBUILD KIT NEW IN BOX
GE FANUC 10 SLOT BASE EMI ENHANCED IC693CHS391K
ALLEN BRADLEY 194R-NN030P3 SAFTEY SWITCH 30 AMP ?
VICKERS 120 VAC SOLENOID COIL PART# 868982 NEW
H5CL-A OMRON TIMER
GE FANUC OUTPUT 12/24 VDC 16PT MODEL# IC693MDL740E
CHROMALOX TEMP CONTROLLER MODEL 3912-10104 REFURBISHED
NEO-DYN INC. ADJUSTABLE AIR RELAY SWITCH 100PV2-4F3
ALLEN BRADLEY 1746-IO12 COMBINATION OUTPUT MODULE
SOLA GLS-03-200 POWER SUPPLY 15V OUTPUT NEW
ALLEN BRADLEY 1747-DCM DIRECT COMMUNICATION MODULE
HONEYWELL PRESSURETROL L404 C 1147, 0-15 PSI
9007C54B2 SQUARE D LIMIT SWITCH NEW IN BOX
Tri-Tronics BF-A-72TP Light Guide NEW IN BOX
204CD ALCO SOLENOID VALVE NEW IN BOX
121WB 03P02 ALCO SOLENOID VALVE WATER SERVICE NEW
303G-111D-1 MAC VALVE NEW
6233C-000-PM-11?1DA MAC VALVE NEW!!
S82H-3524 OMRON POWER SUPPLY NEW IN BOX
SR552A9A REGENT ALL-SOLID-STATE SENSING RELAY
C500-OA222, 3G2A5-OA222 OMRON OUTPUT UNIT NEW
KEYENCE FS-V1P PHOTOELECTRIC AMPLIFIER FIBER OPTIC?
F25242-311 ARO FILTER AUTOMATION DRAIN W/INDICATOR NEW
HAWKEYE 540NS STATUS SENSOR/COMMAND RELAY
IC630MDL301A GE FANUC INPUT MODULE?
355-021-019 DEUBLIN UNION NEW IN BOX
SLS-24-120T SOLA HEVI-DUTY POWER SUPPLY NEW IN BOX
