编程语言的形式
本教材采用常用的两种编程语言，一是梯形图，二是助记符语言表。采用梯形图编程，因为它直观易懂，但需要一台个人计算机及相应的编程软件；采用助记符形式便于实验，因为它只需要一台简易编程器，而不必用昂贵的图形编程器或计算机来编程。
虽然一些的PLC还具有与计算机兼容的C语言、BASIC语言、专用的语言（如西门子公司的GRAPH5、三菱公司的MELSAP），还有用布尔逻辑语言、通用计算机兼容的汇编语言等。不管怎么样，各厂家的编程语言都只能适用于本厂的产品。
l编程指令:指令是PLC被告知要做什么，以及怎样去做的代码或符号。从本质上讲，指令只是一些二进制代码，这点PLC与普通的计算机是完全相同的。同时PLC也有编译系统，它可以把一些文字符号或图形符号编译成机器码，所以用户看到的PLC指令一般不是机器码而是文字代码，或图形符号。常用的助记符语句用英文文字（可用多国文字）的缩写及数字代表各相应指令。常用的图形符号即梯形图，它类似于电气原理图是符号，易为电气工作人员所接受。
l指令系统:一个PLC所具有的指令的全体称为该PLC的指令系统。它包含着指令的多少，各指令都能干什么事，代表着PLC的功能和性能。一般讲，功能强、性能好的PLC，其指令系统必然丰富，所能干的事也就多。我们在编程之前必须弄清PLC的指令系统
l程序:PLC指令的有序集合，PLC运行它，可进行相应的工作，当然，这里的程序是指PLC的用户程序。用户程序一般由用户设计，PLC的厂家或代销商不提供。用语句表达的程序不大直观，可读性差，特别是较复杂的程序，更难读，所以多数程序用梯形图表达。
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Cincinnati Milacron 3-531-3597A ESD Circuit Board
SIEMENS C98043-A1047-L Control Board
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Mitsubishi FX-1HC MELSEC Counter Block Module
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Fisher PROVOX CL6872X1-A2 Analog Termination Panel
Mitsubishi AY40 MELSEC PLC Module
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GE Fanuc IC697MDL653 E Series 90-70 Input Module
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Rexroth VT5007 Proportional Amplfier Module
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Allen-Bradley 700-PSRPA1 Solid State Timer
Allen-Bradley/DataMyte 862-04A-01-EN Data Terminal
Refurbished Cincinnati Milacron 3-533-0040G Board
Refurbished Cincinnati Milacron 3-533-0127G Board
Refurbished Cincinnati Milacron 3-533-0098G Board
Fisher PROVOX CL6741X1-A2 Discrete I/O Term. Panel
NEW Reliance Electric 0-54204 31C57 Error Detector
Barber-Coleman 10EV-0JF00-000-5-00 Temp. Controller
RSF Elektronik MSA 6701 320mm Linear Scale/Encoder
OMRON C120F-CPUA7-EQ Programmable Controller
Stanley Air Tools X5625 SMA8215-SAT-1C Control Module
STI FS4312B-2R-3 FLEXSAFE RX END SEGMENT RECEIVER
Honeywell 30751856-001 Operator Station Memory Board
STI FS4312B-2X-1 FLEXSAFE TX FIRST SEGMENT TRANSMITTER
STI FS4312B-2R-1 FLEXSAFE RX FIRST SEGMENT RECEIVER
Allen-Bradley 7300-UPX-1 CNC Control Board
Allen-Bradley 1771-OFC/B Analog Output Module
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Honeywell 30757569-001 DR4500A Processor Board
Philips MM26 Control Board
Schneider Modicon Premium TSXDET16D2 Input Module
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Bailey Controls 6635176J1 U/V Receiver Board
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OMRON F300-A22S VISION MATE CAMERA I/F UNIT
Pepperl + Fuchs IVI-KHD2-4HRX IDENT-1 Interface Module
ALLEN-BRADLEY 50381 REV. 05 SPEED METER MODULE
FANUC A20B-2900-0340/03A Control Module
Rosemount SCL-C-005-M2 SOLU COMP Water Analyzer
ALLEN-BRADLEY 50917 REV. 03 SIGNAL CONDITIONER MODULE
FANUC A20B-2901-0480/02B POWER MATE Control Module
FANUC A20B-0008-0240/02/08D Orientation Control Board
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Modicon 100-0021 REF/TIMER Control Board
AEG Modicon PC-0984-385 Programmable Controller
ALLEN-BRADLEY 1771-HM3A 64KW CMOS MEMORY MODULE
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FANUC DEC-32VO LM726HNW Display Board
Indramat LK SIO 04-B PC 104 Serial Interface W/Cables
Refurbished Allen-Bradley 1785-KA Comm. Adapter Module
FANUC A14B-0061-B103-03 Input Unit
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NEW Reliance Electric VU4000869 Control Board
FANUC A20B-2900-0310/04A Graphics SMD Module
Honeywell 30750786-001 EDAC Memory Board
STI FS4312B-2X-3 FLEXSAFE TX END SEGMENT TRANSMITTER
(3) NEW Fisher PROVOX CL6851X1-A2 Iso. Voltage Module
Honeywell 82408485-001 SBLA-III Control Board
OMRON C120F-CPUA7-EQ Programmable Controller
NEW Allen-Bradley 5370-MPK Vision Input Software Kit
Foxboro CM902WM I/A Series 3A Power Module Rev. A
Foxboro CM902WX I/A Series Power Module Rev. 0E
Allen-Bradley 1773-L1A PLC-4 Microtrol Controller
Modicon 100-427 BD 3240 6X48K Module
New RTP 021-0161-009 Rev. BB 7455 4-CH Analog Output
New RTP 021-0210-010 Rev. R 8436/SS AI Gate Board
NEW Honewyell Microswitch LSXM4N X-Proof Limit Switch
Cincinnati Milacron 3-531-3283A ACO Circuit Board